Asian Digital Modeling Contest 2017

ADMC 2017
C a t a l o g u eAsian Digital Modeling Conte st 2017
ADMC 2017 Catalogue
Editors of ADMC 2017 Catalogue
Kunio KONDO
Jun MITANI
Misako NISHII
Hisashi SATO
DesignAya SAITO
Organized by
Japan Society for Graphic Science (JSGS)The University of Tokyo, Komaba I Campus
3-8-1 Komaba, Meguro-ku, Tokyo 153-8902
Contact: info-admc2017@graphicscience.jp
This contest is supported by JSPS KAKENHI Grant Number JP16HP0706.
Printed by
Sobun Printing, Co., Ltd.
Published in October 2017.
Copyright© 2017 Japan Society for Graphic Science. All Rights Reserved.

Contents

Asian Digital Modeling Contest 2017..................................................................

2

Jury Committee, Executive committee ................................................................

3

Comments by ADMC2017 Jury...........................................................................

4

Introduction to Award Winners.............................................................................

5

Grand Prize “Duality”...........................................................................................

8

Award for Excellence “Pre-programmed deformable material”........................... 12Award for Excellence “Chladni Towers”.............................................................. 14
Special Jury Award “OJIGI TOKURI”................................................................. 18
Finalist “Capricious Hearts”................................................................................ 22
Finalist “3D PINTED MODEL AS AUGMENTED REALITY MARKER”....... 24
Finalist “Design by Spheres – A Project for Museum”......................................... 28
Finalist “Design lamp shade”................................................................................ 32
Finalist “Triskelion Blocks”.................................................................................. 34
Finalist “Natalie’s Ramonda pavilion”................................................................. 38
Finalist “3D-Materials for Mechanical Design and Drawing Education--Technical Assistance Through Experience”......................................... 42
Report on How to Construct 3D Models for 3D Printing..................................... 491

Asian Digital Modeling Contest 2017

Asian Digital Modeling Contest 2017
The Asian Digital Modeling Contest 2017(ADMC2017) will be held in conjunction with the 11th Asian Forum on Graphic Science(AFGS2017) which is primarily sponsored by the Japan Society for Graphic Science. ADMC2017 is presently inviting original 3D
models which can be built using 3D printers. The contest aims to spread fundamental technologies for inspiring the creation of threedimensional mechanisms and objects in new innovative environments led by additive manufacturing (3D printers). Over the past 10
years, the Japan Society for Graphic Science has been holding the Digital Modeling Contest in Japan. Based on its experience
accumulated through these contests, this time the society expanded the areas eligible for entering works and invited entries fromabroad. Entries selected for the final round be attended to make a presentation on their work and participate in the poster exhibition in
the final judgment of ADMC2017 held during AFGS2017.
3D printers are used widely, from making machines to architecture, molding designs, everyday goods, toys, characters, and so on.
The 3D data used is made by methods which continue to progress based on innovative concepts and technologies such as creating
modeling data by measuring target objects using 3D scanning devices, large-scale shape data processing, etc. In the areas of robot
engineering and medical engineering for example, 3D printers are used to build 3D models for resolving various problems. We
welcomed entries from areas developing such novel applied technologies, 3D shapes made by additive manufacturing, 3D models
built using original and innovative 3D shape production methods, etc. For details of digital modeling contests held by Japan Society
for Graphic Science in the past, please access: http://www.graphicscience.jp/contest/list.html

Judging schedule
August 7, 2017

Short talkAugust 8, 2017

Gallery talkAugust 10, 2017 Awards ceremony

Venue
21 Komaba Center for Educational Excellence (21 KOMCEE)
the University of Tokyo, Komaba I Campus
3-8-1 Komaba, Meguro-ku, Tokyo 153-8902

2

Jury Committee, Executive committee

Jury Committee

Cosponsors

Jury committee Chair

ALTECH Co., Ltd.
Autodesk, Inc.

Jun MITANI Japan

Lattice Technology Co.,Ltd.

Jury committee Vice-Chair

Stratasys Japan Co.,Ltd.

Misako NISHII Japan
Jury committee members

Contact

info-admc2017@graphicscience.jp

Erik DEMAINE USA
Organized by Japan Society for Graphic Science

Sang Kwon GOO Korea
Yasushi IKEDA JapanEri MATSUI Japan

This conference is supported
by JSPS KAKENHI Grant
Number JP16HP0706.

Henry SEGERMAN USA
Yongtian WANG China
Hisashi SATO Japan
Tsutomu ARAKI Japan
Michio KATO Japan
Aya SAITO Japan
Tatsushi TANAKA Japan
Emiko TSUTSUMI Japan
Yasushi NIITSU Japan
Koichi MATSUDA Japan
Yoshiaki MACHIDA Japan
Toshio MURAMATSU Japan
Kazuko MENDE Japan
Tatsuya MOCHIZUKI Japan
Yohei NAMBU Japan
Yayoi YOKOYAMA Japan
Executive committee Chairman
Kunio KONDO Japan
Vice-chairman
Hisashi SATO Japan
Misako NISHII Japan
Committee member
Ryuta MOTEGI Japan

3

Comments by ADMC2017 Jury

selected 11 finalists.

1. Comments by ADMC2017 Jury
Over the past 10 years, the JSGS (japan society of graphic
science) has been holding the Digital Modeling Contest in(3) Election of Awards from finalists

Japan. Based on its experience accumulated trough these

A short talk session and a gallery talk session were held on

contests, JSGS decided to hold ADMC2017. We expected

7th and 8th Aug respectively. The nominees holdmore submissions. There were 27 submissions from 7

presentations with slides at the short talk session. The posters

different countries including Asia and Europe. All of theand the 3D printed objects were presented at the gallery talk,works were very interesting. Many of the works showed theand the nominees answered questions from jury members

possibilities of Digital Modeling and 3D printers. Some ofand participants of ADMC and AFGS. Each jury committee

the works showed that it is possible to make shapes using 3D

member selected three excellent works and voted for them

printers in various fields such as education, medical care andwith comments. After the gallery talk session, a jury

so on. There were also some works showing the difference

committee held a meeting. After a discussion based on the

between existence as digital data and as a real object. We

vote result, nominees for one grand prize, two award forbelieve that this contest shows the possibility of 3D printers

excellences, and one special jury award were selected.

and Digital Modeling.
(4) Award Winners
Grand Prize

2. Judging and Awards(1) Judging criteria

Duality: Masanori Nakayama, Issei Fujishiro

Entries are judged according to the following criteria comAward for Excellence

prehensively.

Pre-programmed deformable material:■Modeling ability· Ability to build 3D data and models taking into accountTaisuke Ohshima, Tomohiro Tachi, Yasushi Yamaguchi

the ideas and method for building the model.

Chladni Towers: Martin Skrodzki, Ulrich Reitebuch,■Structures and mechanisms possible with 3D printers

Konrad Polthier· Complicated mechanisms which could not be built easily
Special Jury Awardwith cutting techniques and casting until now.

OJ IGI TOKURI: Shoko KAWATA, Kazuki TAKENOUCHI· Materialization of geometrical figures.
■New fields of application· Use of 3D data for new fields for resolving various tasks.
(2) Selection of finalists
We had 27 submissions from 7 different countries, and we4Introduction to Award Winners

Grand Prize
Duality

Masanori Nakayama, Issei Fujishiro

Awards reason:
The algorithms for Voronoi diagrams and Delaunay diagrams are employed for the modeling process. It is impossible to create
the form without digital modeling techniques. It is a representative model of the challenges that today’s 3D printing is facingsuch as generative algorithm, mesh generation, and weight saving. The appearance of its precise structure is beautiful. The
technique of setting different strength place by place could be practically used in the medical field for when 3D printing theshape of the internal organs.

Award for ExcellencePre-programmed deformable material Taisuke Ohshima, Tomohiro Tachi, Yasushi YamaguchiAwards reason:
Although almost rigid materials are used, it succeeded to generate the intended curved surfaces from a flat sheet by controlling
its geometrical pattern. It is surprising that curved surfaces with different Gaussian curvatures can be created from regular andsimple patterns. This structure has potential to be applied to new material design in many industry fields.

Award for Excellence
Chladni Towers

Martin Skrodzki, Ulrich Reitebuch, Konrad PolthierAwards reason:
The form is constructed from a layered Chladni figure which is derived from physical phenomena. Visualization of sound is often performed by two-dimensional figures, but by using a layered structure, an additional dimension is expressed in the height
direction, and the vibration of sound is expresses in a 3D space. The idea is novel and the realized form is elegant. This is asplendid work that visualizes an invisible physical phenomena.

Special Jury AwardOJIGI TOKURI

Shoko KAWATA, Kazuki TAKENOUCHIAwards reason:
It has succeeded in designing a novel Tokuri, a Japanese traditional sake bottle, which has new functions and values with a humorous point of view. Japanese tradition and fabrication technique are well integrated, and its geometrical form is also attractive.

5

Award Winners & Finalist

Grand Prize

Duality
Masanori Nakayama, Issei Fujishiro

Masanori Nakayama, Issei Fujishiro “Duality” 2017, Material: VeroWhite, Size: 246W x 120D x 189H (mm)In the present work, we attempted at expressing human “two-facedness” by the “two-sidedness” of the 3D structures. In the field ofgeometry, there exists a two-facedness called “duality,” which represents the relationship between diagrams that switch between faces(cells) and vertices. Delaunay diagram and Voronoi diagram give a typical example. We have developed an algorithm to generate a
Poisson-disk distribution in an arbitrary shape to make sculptures with those diagrams. The Delaunay diagram generated by Poissondisk distribution point cloud makes up the uniform tetrahedral mesh (except for the surface). Since those cells are close to a regulartetrahedron, Voronoi vertices located on the circumcenters also have an almost uniform distribution.

8

Grand Prize

Keywords: Tetrahedralization, Delaunay diagram, Voronoi diagram

1 Concept

region into a uniform triangular mesh with Poisson disk

We have worked on an optimal subdivision algorithm to

distribution (Fig. 1). By embedding the 2D Delaunay

discretize a given arbitrary shape. In 2D, we built on

diagram in 3D, we succeeded to subdivide an arbitrary closed

Delaunay diagram to subdivide an arbitrary closed curve

surface volume into a tetrahedral mesh with Poisson disk9

Grand Prize

Figure 1: Poisson-disk triangulation.

distribution (Fig. 2). In comparison with Guo’s prior work[2], the incorporated non-polygonal isosurfacing increases
the versatility in terms of input volume, simplifies meshingsteps, and improves the quality of output meshes.
All of our works root commonly in the “duality” of Delaunay
diagram and Voronoi diagram―both structures are mutuallyconvertible by swapping the roles of faces and vertices. In
the present work, we attempted at expressing human “two-Figure 2: Poisson-disk tetrahedralization.

facedness” with the “two-sidedness” of the two diagrams.

shape. Fig. 3 simply represents this in 2D.

2 How to Make

Next, we add points only in the inside region. Note that in

There exists a de facto standard tetrahedralization libraryorder to uniformly distribute vertices, we should not insert

called Tetgen [3]. For edgy curve surfaces that can bethem randomly. For each tetrahedron, we search for thedefined in a piecewise manner, a specific type oflargest circumscribed sphere, and insert a point at the centertetrahedralization algorithm was devised in [4].

of the sphere (Fig. 4). The position of the point is nothing

In our tetrahedralization scheme, we first generate aless than the vertex of the Voronoi diagram, indicating theDelaunay diagram with vertices on the target’s surface, andmost distant location from the existing points in the largest

thereby making separate inside and outside of the target

blank area.

10Grand Prize

Figure 3: Delaunay diagram of edge points.

By repeating the process, the vertex distribution automatically converges to a Poisson disk distribution, and resulting in

Figure 4: Voronoi vertices in empty circle.

the most uniform tetrahedral mesh. Variational tetrahedral

Referencesmeshing in [1] can further improve the location of all the[1] P. Alliez, D. Cohen-Steiner, M. Yvinec, M. Desbrun,vertices gradually, but works slowly.

Variational tetrahedral meshing, ACM Transactions on

In the process, the Voronoi diagram is generated together

Graphics, Vol.24, No.3, pp. 617–625, 2005.

with the Delaunay diagram, whereas the Voronoi diagram[2] J. Guo, D. Yan, L. Chen, Tetrahedral meshing via maxi-

itself has no utility value. In the present work, however, by

mal Poisson-disk sampling, Computer Aided Geometricjuxtaposing the two diagrams, we intended to express the

Design, Vol.43, No.C, pp. 186-199, 2016.

interest of geometry.

[3] H. Si, Tetgen, a Delaunay-based quality tetrahedral meshgenerator, ACM Transactions on Mathematical Software.

3 Software & System

Vol.4, No.2, Article 11, 2015.

All the programs have been implemented in the Object Pas-

[4] J. Tournois, C. Wormser, P. Alliez, M. Desbrun, Inter-cal language using an integrated development environment

leaving Delaunay refinement and optimization for practi-

Embarcadero Delphi. For editing/rendering the model, thecal isotropic tetrahedron mesh generation, ACM Transac-

3DCG software Cinema 4D was used.

tions on Graphics, Vol.28, No.3, Article 75, 2009.

11

Award for ExcellencePre-programmed deformable material
Taisuke Ohshima, Tomohiro Tachi, Yasushi Yamaguchi

Taisuke Ohshima, Tomohiro Tachi, Yasushi Yamaguchi “Pre-programmed deformable material” 2017, Material: VeroWhite, Size: 320.1W x 181.5D x 6.6H (mm)“Pre-programmed deformable material” is a material which transforms into preprogrammed shape. It’s flexible in one preprogrammed
deformation but stiff in the other deformation. The transformation into freeform curved surfaces from flat state is difficult because it
should have three different Poisson’s ratio within one material. The Poisson’s ratio is related to Gaussian curvature in surfaces ofdeformation, ie. positive Poisson’s ratio realizes curved surfaces whose Gaussian curvature is negative and negative Poisson’s ratio
realized curved surfaces whose Gaussian curvature is positive. Proposed material has explicitly distributed Poisson’s ratio andrealizes double curved freeform surfaces.

12Award for Excellence

Description
We propose structures to transform into
preprogrammed surfaces (Figure 1). Submitted material is the structure that transforms into torus. The torus is a surface withthree Gaussian curvatures (K), negative,
zero and negative. If the deformation shape
is K ≤ 0 such as saddle shape or developable surfaces, materials must have positive
poisson’s ratio. However, if K > 0 such as
dome shape, materials must have negative
poisson’s ratio (Figure 2).
Proposed material has combined threeGaussian curvatures and corresponding
three poisson’s ratio. In order to generate

Figure 1: Proposed structure

this structure, we developed original
software. This software is the system togenerate structure from target shape. Target
shape is defined by principal curvaturelines. Generated structure naturallytransforms into target shape from simple
external force.

Figure 2: Three structures used in proposed materials. K is Gaussian curvature.

13

Award for Excellence

Chladni Towers
Martin Skrodzki, Ulrich Reitebuch, Konrad PolthierMartin Skrodzki, Ulrich Reitebuch, Konrad Polthier “Chladni Towers” 2017, Material: RGD720, Size: 101.6W x 101.6D x 103.4H (mm)In 1802, Ernst Florens Friedrich Chladni published his book “Acoustics” containing visualizations of vibration modes in 2D. We
generalize the well-known concept to 3D. Via computer simulations, we solve a corresponding physical system and thereby obtain an
isosurface in a cubical model. This isosurface visualizes the elimination of sound waves and their reflections, showing points in threespace where different frequencies vanish. Using a 3D printer, these vanishing points can be physically realized. Application are given
in instrument design or architecture of music halls. With transparent filament, constructors or architects can print problematic regions
directly into their prototypes for awareness.

14

Award for Excellence

Keywords: Vibration Modes, Acoustics, Chladni Figures

Figure 1: Left: Portrait of Ernst Florens Friedrich Chladni by H. Adlard, 19th Century. Center: Illustration of the violin bow experiment, takenfrom [3]. Right: Table of Chladnis figures from Chladni’s book “Acoustics”, 1802.

Margaret Watts-Hughes, Henry Holbrook, or Hans Jenny

1 Introduction

have further developed the Chladni experiment [1]. Despite

In 1802, Ernst Florens Friedrich Chladni (November 30th,
1756 – April 3rd, 1827, see portrait in Figure 1) published
his book "Acoustics". The book describes amongst otherthings an experiment by which different modes of vibration
can be visualized. Namely, sand is distributed over a thinmetal plate. A violin bow is then struck alongside the plate,causing it to oscillate, see Figure 1 for an illustration. Chladni
found that the sand grains form different patterns
corresponding to the varying vibration modes of the plate.
His book contains a table of patterns he was able to create in
his experiments, see Figure 1.

Figure 2: Application of Chladni Figures in building musical instruments.

Since its first description, several other scientists like15

Award for Excellence

their elegance and artistic value, Chladni figures have

Applications of our method can be found for example inapplications in the construction of musical instruments as

Architecture, where the printed model gives an impression ofillustrated in Figure 2.

the acoustics of a given room.

We generalize Chladni’s concept to the third dimension. In
terms of a corresponding physical experiment, this consists

2 Physical and Mathematical Backgroundof distributing light particles in some viscose fluid. For ex-

For simplicity, we generalize Chladni’s patterns from theample, speakers are then used to stir the fluid and the parti-

square-shaped plate to a cubical model. In the following, ourcles form stable patterns, just as in the two-dimensional case.

cube will be assumed to occupy space [-1,1]³. Starting from

However, we do not build a physical experiment, but

the physical formulation of a damped oscillation of a string,

simulate the outcome of it, to print it via a 3D-printer.

we combine the solutions to the wave equation to obtain a

16

Award for Excellence

formulation of a one-dimensional Chladni pattern as the zero

Given the first rough visualizations, more elaborate pictures

set of an expression on the string. From this formulation, welike the title image are created with the PovRay Raytracer

can obtain a three-dimensional pattern as the zero-set of thesoftware [6]. Finally, from these, a model is chosen for 3D

following expression:

printing.

A · sin(μ · π · x) · sin(ν · π · y) · sin(w · π · z)
+B · sin(μ · π · x) · sin(ν · π · y) · sin(w · π · z)

Table 1: Exact parameter values of the “Chladni
Towers” Model+C · sin(μ · π · x) · sin(ν · π · y) · sin(w · π · z)
+D · sin(μ · π · x) · sin(ν · π · y) · sin(w · π · z)

Objects
Integral Parameters
Real Parameters+E · sin(μ · π · x) · sin(ν · π · y) · sin(w · π · z)
+F · sin(μ · π · x) · sin(ν · π · y) · sin(w · π · z).
Note that the formulation permits two different types ofCaptionu=1, v=2, w=4
A=0.5, B=0.0, C=0.5,
D=8.0, E=0.5, F=8.0

figures: Those with sine (as shown) and those with cosine
formulations. These correspond to different boundary

Referencesconditions on the wave equation. For further details on the[1] Findeiß. F., Die Entdeckung der Chladnischen Klangfig-

mathematical and physical background, as well as otheruren. Ursprünge und Weiterentwicklung im historischen

visualizations, see [2].

Kontext (in German). Leuphana Universität Lüneburg,

The particular model generated for the Asian Digital Model-

Germany, 2015.

ing Contest and shown as title image has been named[2] Skrodzki, M., Reitebuch, U., and Polthier, K., Chladni“Chladni Towers”. Its exact parameters are given in Table 1

Figures Revisited: A Peek Into The Third Dimension.

and it corresponds to Dirichlet boundary conditions on theProceedings of Bridges 2016: Mathematics, Music, Art,

wave equation.

Architecture, Education, Culture. pp. 481-484, 2016.
[3] Stone, W.H., Elementary Lessons on Sound, Macmillan

3 Software & System& Company, 1879.

Our approach consists of plotting the zero level set of the[4] Lorensen, W.E. and Harvey, E.C., Marching cubes: A

expression given above in a cubical bounding box. Thishigh resolution 3D surface construction algorithm. ACM

corresponds to visualizing the isosurface given by the

Siggraph Computer Graphics, Vol. 21, No. 4, pp. 163-

expression. To do so, we utilize the marching cubes

196, 1987.

algorithm [4]. The algorithm has been implemented in the[5] Polthier, K. et al, JavaView, www.javaview.de

JavaView Framework [5]. Within this framework, we[6] Persistence of Vision Pty. Ltd. Raytracer (version 3.7),

visualize the zero set for different prescribed values of

http://www.povray.org

17

Special Jury AwardOJIGI TOKURI Self-Tilting Sake Bottle
Shoko Kawata, Kazuki Takenouchi

Shoko KAWATA, Kazuki TAKENOUCHI “OJIGI TOKURI (Self-Tilting Sake Bottle)” 2017, Material: VeroWhite, Size: 94W x 94D x 86H (mm)OJIGI TOKURI can tell the remaining quantity of sake inside by changing its tilting position, while remaining sake is invisible in a
traditional one made of opaque china. This unique behavior of the tilting is generated by its computationally optimized asymmetricalinner configuration, which changes the center of gravity with a decrease of sake with holding a stable tilting position in 4 steps.
Moderate movement to the next stable position is given by double curved surface patches. Elegant openwork and deep extrude cut
figured with cherry blossoms implicitly show the mechanism of tilting.

18

Special Jury Award

Keywords: Digital modeling, Digital fabrication, Statics, Tokuri, Optimization, Engineering calculation

1 Introduction

The authors’ work OJIGI TOKURI at the top of this page

In a Japanese traditional style of drinking sake for two, sakehelps drinkers and servers see the quantity of sake in the bot-is served in a tokuri, one of Japanese traditional bottles fortle without impolite behaviors by tilting depending on the re-sake holding standard content volume of 180ml or 360ml

maining. The name OJIGI TOKURI comes from a Japanesecalled as 1-gou toukri or 2-gou tokuri, respectively. As a

traditional greeting, ojigi, making a bow; tilting behavior ofmanner in this case, drinkers are expected to fill sake eachtokuri is similar to ojigi in terms of both moving and having

other into partner’s small sake cup, sakazuki, and at every

some of degrees as illustrated in the top right figure.

filling sake in the tokuri gradually reduces. As such tokuri isin general an opaque china, the remaining quantity is esti-

2 Idea and design requirements

mated by shaking the tokuri or by looking into it, and theSince tilt of OJIGI TOKURI is caused by a move of theempty tokuri is often laid down as a sign of drinking up. All

center of gravity with a decrease of sake in tokuri, its

these behaviors are however against good manners.

asymmetrical inner surface configuration not interfering with19

Special Jury Award

the flow of sake should be carefully determined to satisfy the

inclination for each particular quantity of sakestatics in accordance with the outer contour. In addition to· tilting with moderate motion not to pour out thesake in tokuri nor break itself by impact

the above requirements, the authors imposed following
design requirements to the tokuri for a practical use:

In order to simultaneously meet these complex requirements,· holding the standard content volume (180ml)

a numerical evaluation is necessary on geometry and statics· visualizing a quantity of remaining sake with somefor a tentatively determined configuration at every tilting

tilting degrees and staying stable at rest in a single

position followed by a modification to a better result.

20Special Jury Award

3 Modeling environment and procedure

4 Final model of OJIGI TOKURIAs design of such a novel product is a creative work,

The final model is shown at the top of the first page and insuccessive modification and even introduction of addtional

Fig.2(b). The behavior has been improved through the fiverequirements and constraints found out in the process will be

prototypes fabricated with FDM 3D printer as shown in Fig.3

required. To handle such process, the configuration of tokuri,from the left to the right.

cross-section of outer and inner surfaces, was evaluated and

The five prototypes are constructed with an axially

optimized by use of spreadsheet, not special CAE tools nor asymmetrical outer surface or combination of ruled surface;programing languages that require special knowledge andthe final model is constructed with small curved surface

skills to users. Furthermore, as shown in Fig.1(a), the users

patches. The patches are generated by connecting regularcan confirm calculated results by instantly illustrated outline

octagons by use of loft surface, one of the most fundamentalof the tokuri and the position of center of gravity at eachfunctions of 3D CAD, octagons which are storied along

tilting position as 2D plots.

tokuri’s centerline with a relative revolution between the

Digital 3D modeling of the tokuri was carries out on Fusionneighboring two polygons. Such curved surface patches

360: 2D sketch was drawn by tracing the profiles determinedseem to be effective to give OJIGI TOKURI a moderate

based on calculation on spreadsheet, and 3D surfaces intilting motion to a feasible direction, being expected to avoid

Fig.1(b) were generated based on the sketch. Its outer andtokuri rolling off the table and being damaged by the impact.

inner surfaces were then joined into a solid body in Fig.1(c).

To control its tilting behavior, an appropriate fillet size is

Finally, openwork and lightening in Fig.1(d) were added forchosen for each edge of patches.

better performance of tokuri.

The contour of the bottom face is a circle for a smooth start

The openwork is partly for a better performance by makingof tilting. Surface cut with a truncated circular cone isfine adjustment, and also for disclosing the existence of inner

applied for the connection between the circular bottom facepartition, impressing the mechanism of generating its

and the octagonal section.

interesting behavior. In the modeling of the openwork,

Also to implicitly show the existence of solid weight

Boolean operation was applied with a basic solid pattern

opposite to the hollow partition, the other mechanism of theshown in Fig.2(a) and arranged on the shell of hollowed area

tilting behavior, rather deep extrude cuts having a contour ofin Fig.2(b).

flower are added.

21

Finalist

Capricious Hearts
Kokichi Sugihara

Kokichi Sugihara “Capricious Hearts” 2017, Material: RGD720, Size: 249.6W x 74.4D x 127.2H (mm)The object appears to be four hearts in a line when we see it directly, but the reflection in a vertical mirror behind the object appears
to be the set of all four suits of the trump, i.e., diamond, club, heart and spade. We know that the shape of an object and its mirror
image are mirror symmetric to each other, and hence heart cannot change to diamond, etc., in a mirror; the behavior of this object
seems impossible. However, this is possible because our perception is subject to optical illusion.

22

Finalist

Keywords: ambiguous cylinder, impossible object, optical illusion

1 Behavior of the Object
From a special viewpoint it appears to be four hearts in a

apt to interpret 2D images as 3D objects with as manyline, but if we rotate it around the vertical axis by 180

rectangles as possible [3]. Hence, if we present cylindricaldegrees, it appears to be the set of all four suits of the trump,shape with a constant height, we usually interpret the edge

i.e., diamond, club, heart and spade. These two appearances

curve of the cylinder as a plane curve perpendicular to thewill be enjoyed at the same time if we place a vertical mirror

axis of the cylinder, even if it is a space curve.

behind the object and look at the object and its mirror image

Combining these two observations, we can constructsimultaneously.

ambiguous cylinders. This is the basic idea for ambiguous

We know that the shape of an object and its mirror image arecylinders. I applied this method to four pairs of shapes, one

mirror symmetric to each other, and hence heart cannot

is heart and the other is one of the four suits of the trump,change to diamond, for example, in a mirror; the behavior ofand thus generated four ambiguous cylinders. Finally I

this object seems impossible. However, this is possible

joined them to the present object

because our perception is subject to optical illusion.

3 Software & System

2 Production Process

With my original program written in Fortran, I computed the

I found a systematic method for creating a new class ofshape of four objects corresponding to the four suits, andimpossible objects, which I named “ambiguous cylinders.”

then generated their STL data. Finally, using theThis class of objects generates optical illusion in the sensecommercialized modeling tools Rhinoceros version 5.0, I

that their appearances change drastically in a mirror [1]. The

merged them into one final object.

ambiguous cylinders are based on two observations, one is
physical and the other is psychological.

References

Physically, a single image of a 3D object does not have[1] Sugihara, K., Ambiguous cylinders: A new class of im-

information about depth, and consequently there are infinitely

possible objects. Computer Aided Drafting, Design andmany possible 3D objects that yield the same 2D image [2].

Manufacturing, Vol.25, No.3, pp.19-25, 2015.

Hence, we can generate a 3D object that has two desired 2D[2] Sugihara, K., Machine Interpretation of Line Drawings.

appearances when seen from two special viewpoints, if the

MIT Press, Cambridge, Massachusetts, 1986.

pair of appearances satisfies a certain condition.

[3] Perkins, D. N., Visual discrimination between rectangu-

Psychologically, on the other hand, our vision systems have a

lar and nonrectangular parallelopipeds. Perception andstrong preference for rectangularity in the sense that we are

Psychophysics, Vol.12, pp.293–331, 1972.

23

Finalist

3D PRINTED MODEL AS AUGMENTED REALITY MARKER
Petar Pejic, Sakan Srdjan, Sonja Krasic

Petar Pejic, Sakan Srdjan, Sonja Krasic “3D PRINTED MODEL AS AUGMENTED REALITY MARKER” 2017, Material: VeroWhite, Size: 198W x 107D x 138H (mm)Virtual 3D model of the complex architectural object, which contain 9 hyperbolic paraboloid is created. 3D model is printed and used
as a marker for visual Augmented Reality tracking. For purposes of this research, we develop android application based on
Augmented Reality technology, which provide additional information on the top of printed 3D model in the form of virtual 3D
geometry, sound and links to additional web resources.

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Keywords: Complex Geometric surfaces, Architecture, Augmented Reality

1 Abstract

2 Model idea

In this research, we create a virtual 3D model of the complex

3D printing, also known as additive manufacturing, hasarchitectural object, which contain 9 hyperbolic paraboloid.

become an established technology in many industry sectors

3D model is printed and used as a marker for visualfor the fabrication of three-dimensional (3D) objects [1].

Augmented Reality tracking. For purposes of this research,Some complex geometric shapes of architectural objects,

we develop android application based on Augmented Reality

such as buildings made of hyperbolic paraboloids are really

technology, which provide additional information in the form

hard to produce. The traditional construction methodof virtual 3D geometry, sound and links to web resources.

assumes use of complex temporary supporting structures,
which usually cost more than the rest of the building [2].
The main inspiration for 3D model was The Philips Pavilion

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Figure 2: SketchUp – 3D model

Figure 1: Original sketch of Philips Pavilion

designed for Expo ’58 in Brussels by the office of Le
Corbusier (Figure 1). The pavilion was designed to house a
multimedia spectacle that celebrated technological progress.
It is a cluster of nine hyperbolic paraboloids in which music,
Edgar Varèse’s Poème électronique, was spatialized by soundprojectionists using telephone dials [3].
Figure 3: Printed 3D model

3 3D model production process
A 3D model is created on the basis of existing sketch andimages [4] using SketchUp [5] software package. A structure

4 Augmented Reality

is created from 9 Hyperbolic paraboloids. Some are only

For purposes of this research android based Augmented

parts, created by cutting them with ground horizontal plane

Reality, mobile application is developed [7], [8]. The(Figure 2).

application uses previously printed 3D model as a marker in

Created 3D model is exported as *STL file and printed usingorder to connect and display virtual data inside real

Ultra 3SP printer [6] (Figure 3).

surroundings.

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References[1] Teizer, J., Blickle, A., King, T., Leitzbach, O. and Guenther, D., Large Scale 3D Printing of Complex Geometric
Shapes in Construction, 33rd International Symposium
on Automation and Robotics in Construction (ISARC
2016), 2016.
[2] Veljković M., Krasić S., Pejić P.: Use of the torus in thedesign of modern architectural structures, The 5th International Scientific Conference on Geometry and Graphics, moNGeometrija 2016., June 23-26, 2016, Belgrade,

Figure 4: Mobile application screenshot

Serbia, pp.445-453, 2016.
[3] https://en.wikipedia.org/wiki/Philips_Pavilion

After starting the application, the device camera records real

[4] http://www.cirma.unito.it

surrounding, while the application is searching for predefined[5] https://www.sketchup.com/

3D model. When the application detects and recognise 3D[6] https://envisiontec.com/3d-printers/industrial- 3d-print-

model, on the device display and speakers additional

ers/ultra-3sp/

information is provided.

[7] Pejić P., Krasić S., Veljković M., Sakan S., Rizov T.:

Detection of 3D model by application activates the originalAugmented and Virtual Reality application in traditional

song “Poème électronique”, composed by Edgard Varèse andarchitectural project presentation - case study of “MH

performed inside the Philips Pavilion.

Petra” house, FME Transactions, Volume 45, No 2, pp.

On the basis of pictures from World’s Fair - Expo ’58 held in

227-231,2017.

Brussels virtual 3D model of the building surrounding is[8] Pejić P., Krasić S., Petković D., Veljković M.: Applica-

created and presented in same scale as printed 3D model.

tion of augmented reality in façade redesign presentation,

Moving the marker will cause a joint move of both the

Journal of industrial Design and Engineering Graphics,

marker and the additional digital content on the device

number 10, ICEGD 2015, SORGING, Romania, ISSN

display (Figure 4).

1843-3766, pp.45-49, 2015.

Taping on printed 3D model inside application provide
additional information about the Philips Pavilion available
on the web. While buttons at bottom of the screen provides
links to ADMC 2017 conference and additional information
about authors.

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Design by Spheres – A Project for Museum
Naomi Ando

Naomi Ando “Design by Spheres – A Project for Museum” 2017, Material: VeroClear, Size: 180W x 90D x 93H (mm)“Design by Spheres – A Project for Museum” is a prototype of a small museum. A total of 12 spheres of varied diameters from 3.2 m
to 16 m were arranged inside a volume space that was 24 m wide, 12 m deep, and 12 m high. Dynamic spaces with spatial
fluctuations were realized by the algorithm to generate spheres with random diameters in random positions. Individual functions, suchas an entrance hall, a lobby, exhibition halls, a terrace, and storages, were given to each sphere, and architectural elements such as
stairways and floors were added. The structure of this museum was assumed to be constructed with reinforced concrete shells of 20
cm to 40 cm thick.

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Keywords: Sphere, Architecture, Algorithmic Design

1 Design by Spheres

spheres with random diameters in random positions.

Spheres, with centripetal spaces inside, have been used as a

Individual functions, such as an entrance hall, a lobby,

motif in various architectural designs, from the Pantheon

exhibition halls, a terrace, and storages, were given to each(ancient Roman architecture) to modern architecture.

sphere, and architectural elements such as stairways and“Design by Spheres – A Project for Museum” is a prototype

floors were added, as shown is Figure 1. The structure of thisof a small museum.

museum was assumed to be constructed with reinforced

A total of 12 spheres of varied diameters from 3.2 m to 16 m

concrete shells of 20 cm to 40 cm thick.

were arranged inside a volume space that was 24 m wide, 12m deep, and 12 m high. Dynamic spaces with spatial

2 Production Processfluctuations were realized by the algorithm to generate

Besides the random values for the diameter and positions of29

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Figure 1: Section of Exhibition Halls

Figure 3: Framework

Figure 2: Arrangement of Spheres

Figure 4: Exploded Diagram

the generated spheres, tangency or overlapping of spheres

the center points were in the [X-Y- Z] region; the radius of

was controlled, as shown in Figure 2. The algorithm was

the spheres varied from [R0] to [R0+R1]; overlapping of thed e s c r i b e d b y V B ( Vi s u a l B a s i c ) c o m p o n e n t o fspheres was allowed if it was smaller than [B]. This method

Grasshopper(1), which is a plug-in for Rhinoceros(2). Byof the “Design by Spheres” was firstly presented at AFGS

this method, spheres were arranged randomly with the2015[1].

following conditions: [N] number of spheres were generated;

Through a number of trials and errors in the automatic gener-30

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Figure 5: Trial Model (support materials are not removed)

Figure 6: Exterior View

Figure 7: Interior Views of the Exhibition Halls(2) Grasshopper: http://www.grasshopper3d.com/

ations, a framework of the model, as shown in Figures 3 and4, was determined. Trial model was fabricated by 3D printer,as shown is Figure 5. Then, some modifications for theReferences

structural rationality and planning efficiency were added for[1] Ando, N. Ishii, S., “Design by Spheres - A Computer
Graphic Material for Architectural Design Education”,

architectural design, as shown in Figures 6 and 7.

Proceedings of the Asian Forum on Graphic Science, P.8

3 Software & System(USB), 2015.

(1) Rhinoceros: http://www.rhino3d.com/

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Design lamp shade
Kimihiro Miura

Kimihiro Miura “Design lamp shade” 2017, Material: VeroClear, Size: 260W x 260D x 310H (mm)This work is a lamp shade which has a rotation mechanism. The inside and the outside of the model rotate separately. By thismechanism, we can enjoy the change of light volume and shadow of the shade. Because the basis and the main body are separated, it
is easy to replace or extend the body to a new design. The size, height, and material etc. may be changed according to the room where
the lamb shade is placed. The users can design and adjust for their own life. From the idea of this work, I hope that lamp shadecreated by 3d printer will be further developed and spread.

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1 Concept

2 ImagesWith the internal and external rotating mechanism, you canenjoy the shadow change, I aimed to be able to use it
according to situations and uses.
It also intended to change the brightness depending on thetype of material of the 30 printer.
The reason why we did not make the base of the lower part
integral is that we have expandability (height, design etc.).

attach image

It is imagining that it can be newly added depending on the

3 Softwer

application.

3ds max2016, photoshop cs6

rotation image

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Triskelion Blocks
Akihiro Matsuura, Hiroshi Shirane

Akihiro Matsuura, Hiroshi Shirane “Triskelion Blocks” 2017, Material: VeroCyan,VeroMagenta,VeroYellow, Size: 75W x 60D x 9H (mm)A triskelion is an iconographic pattern that consists of three legs (or spirals) having three-fold rotational symmetry. We make use ofthis strange but intriguing figure as a motif of our new construction toy. We present two families of triskelion blocks with/without acentral equilateral triangle, where one block is connected to another at its concave parts in three directions. Such connection withsome tiling properties can be effectively used in constructing various shapes using the blocks. One can also enjoy “balancing play” ofphysically standing constructed shapes on the ground which reminds us of coordinated group gymnastics.

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Keywords: triskelion, construction toy, rotational symmetry

1 Basic Ideas & Figures

We make use of this strange but fascinating figure of three

A triskelion or triskele is a classical iconographic pattern thatlegs as motif for our new construction toy. Two basic planeconsists of three spirals placed with three-fold rotational

figures we use are shown in Figure 2 (let us call them figures

symmetry. It is frequently used with a representation of three

T1 and T2). Both figures have three legs with distinct (RGB)

bent human legs, which are seen for example in the flags ofcolors, where the left one has no center triangle but the right

Sicily and the Isle of Man [1] shown in Figure 1.

one has, i.e., the yellow equilateral triangle.

Figure 1: The flag of the Isle of Man

Figure 2: Two triskelion-like figures T1 and T2.

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Figure 6: The family of figures for T1 (leg length = 1, 2, 3).

Figure 3: Connections of T1’s or T2’s and the gymnastic pose.

Figure 7: The family of figures for T2 (leg length = 1, 2, 3).
Figure 4: Circular connection of T1’s and T2’s.

Figure 8: Circular connections for T1-family (leg length = 1,3).

Figure 5: The slilding property of T1 and T2.

The common property of these figures desirable for a con-

physically-balanced two persons, which will make the playstruction toy is that a leg can be connected to the concave

more entertaining and imaginative. Furthermore, thesepart between two legs of another piece as shown in Figure 3,

triskelion-like figures have some beautiful geometricleft. This makes the figures to connect in three directions andproperties on tiling. Namely, six T1’s and six T2’s can behelps to create a variety of shapes. We also emphasize thatconnected in a circular way as shown in Figure 4 and these

the connected figures are just like the gymnastic pose ofconnections are extended infinitely in a recursive way. Espe-

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Figure 9: Circular connections for T2-family (leg length = 1,3).

cially on T1, the central black part is again the shape of T1
and T1’s radially tile the whole plane.
The final typical property of T1 and T2 that we figured out
after prototyping and playing around with the pieces is that

Figure 10: Some constructions.

when we try to disconnect the three pieces from theinterlocking situation in Figure 5, left, we can succeed it byjust sliding two of the pieces, say, green and blue ones sincethen the remaining red piece slides out rather automaticallyvertically and construction can be 3-dimensional. All the

without direct manipulation.

models were designed using the 3D CAD system 123D

Now, we show families of triskelion figures for T1 and T2 that

Design of Autodesk and output in the STL format. The six

preserve the properties of leg connection and recursive tiling.

models are shown in Page 1.

First, we illustrate the family for T1 with leg length 1, 2, and3 in Figure 6 and the family for T2 in Figure 7. (The figures

3 Prototyping & Some Constructionsof leg length 1 are rather exceptional but since they also have

We made prototypes of the blocks using PLA resin and thethe required geometric condition, here we include them).

3D printer Replicator 2. Here we show some of theconstructions using the prototypes in Figure 10.

2 Software & System

The circular connections for the figures in Figures 6 and 7

3D models were made by adding a constant depth to theare shown in Figures 8 and 9, respectively.

figures in Section 1. When the length of unit triangle is 1,
the depth is set to be half of 3 squared, i.e., 0.86 (rounded

Referencesoff) since then the depth parts can be inserted to blocks[1] Triskelion, http://en.wikipedia.org/wiki/Triskelion

37

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Natalie's Ramonda pavilion
Biljana Jović, Komnenov Mirjana

Biljana Jović, Komnenov Mirjana “Natalie's Ramonda pavilion” 2017, Material: VeroWhite, Size: 188W x 188D x 172H (mm)Natural shapes are increasingly used as inspiration for design. Flower forms stand out because of their beauty, so we find theminspiring. The species of choice for us is Ramonda nathaliae P. et P., characterized by unusual traits of poikilohidry and limited range.
Its flower shape is simple and consistent, and therefore a suitable basis for the extraction of the form to be used for generativemodeling. We transformed the surface of flower petals into the Voronoi pattern, generated them using software tools, and developed
them in the model of the Natalie's Ramonda pavilion.

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Keywords: Ramonda nathaliae P. et P., Voronoi, pavilion

1 Ramonda nathaliae P. et P. as inspiration

obtaining a form and therefore transcends that problem [2,3].

More often natural forms are used in the design, whether

Starting from the viewpoint that plants are the most perfectthrough inspiration or literally because of its quality, whether

living organisms, our interest is aimed in their direction.

they are singled out in the structure, function or beauty ofAmong the plants and their organs, there are many variations

form. The possibility of implementing biomimetic principles

in shape, but generally flower stands out as organ that varies

in spatial design, provides an opportunity for thethe least in its form and function, yet because of its beauty

development of different generative model based onparameters that originate from nature, and whose
configuration is adapted to the requirements of spatial
structures [1]. The development of biomimetics and digitaltechnology has found its synthesis in the generative design,
which is driven to a realistic level by digital fabrication.
Implementation of natural forms through the design andspatial structure has so far been limited imitation of organic
forms, however generative design offers unlimited range of

Figure 1: Ramonda nathaliae P. et P. flower

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attracts the most attention [4]. Precisely for these reasons wedeterminated this part of the plant as the basis of our ideas,
and we find inspiration in the flower species Ramonda
nathaliae P. et P.. Ramonda nathaliae Pančić et Petrović isspecies of unusual characteristics having in mind that it ischaracterized by traits poikilohidry and limited range, since
is endemic species in Serbia and Macedonia. Among people
it is also known as the Phoenix flower, because of its featuresthat allows her to survive in state hibernate in unfavorable

Figure 2: Rhinoceros - Grasshopper configuration

conditions and suspend its flowering until favorable
conditions occurs. It was named after Serbian Queenparameters. In this way the arrangement of nerves is

Natalija Obrenovic. This is a perennial plant whose flower

translated into a form whose structure corresponds to thestalks usually carries 1-3 flower. Diameter of each flower issurface of the flower petal.

3-3.5 cm and is characterized by actinomorphic (radial)This structure is flat, and the further procedure of generating

symmetry. The flower is made of 4-5 calyx and 4 articulated

model comes down to bending model surface to obtain aflower petals (exceptionally 5) [5].

wavy shape of the petal. The basic design tools within the

Flower build is simple and consistent, and therefore suitablesoftware package allows us to manipulate this object as partbasis for extraction in the form that will be used to carry outof the design process through which is made a modification

generative model form. In the process we streamed surface

that affects on the spread of the model, the morphologicalof the flower petal into the Voronoi pattern, then generate it

characteristics of form and proportion, changes that manifest

by using software tools, and developed in the model of athemselves visually and directly on the model, until thepavilion.

desired result is achived.
In a further process, the petal has served us as a design

2 Methodpattern. The application of natural form in the framework of

To start, the surface of petals we imagined as a Voronoi grid.

generative design identical to the role of designers who

In the process we used a photograph of the flower [6]. Baseddirects his creative energy in the experiment with a designon the photo and nervs of the flower petals of Ramonda

that offers plenty of opportunities as an outcome of thisnathaliae P.etP., characteristic starting points are positioned

process [7].

as a basis for the future pattern, respectively the centers ofTranslation parameters, which has set itself the nature andcells of Voronoi diagram. Comprehensive Voronoi structure

use them in the experiment search form, it is possible tois derived by applying software Rhinoceros and it plug-in

perform the objects that in essence contains the basic pattern

Grasshopper by linking appropriate components with theflower petal, to obtain a concrete model. In a further stage of40

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i5 Intel Core x64-based processor and 6 GB of RAM. In aprocess we used Rhinoceros software with Grasshopper
plug-in.

Acknowledgement
Authors are supported by the Ministry of Education, Scienceand Technological Development of the Republic of Serbia,
Project No TP36008.

References[1] Milošević J., Nestorović M., Bio-interfaces, Studies in

Figure 3: Pavilion implemented in the space

Bionics and Space Structure Design, 4th International
Scientific Conference on Geometry and Graphics,

searching a suitable form so that we can take advantage of

moNGeometrija, Vlasina, Vol.1, pp.90-99, 2014.

the resulting Voronoi pattern we have come to pavilion
model. Voronoi structure is limited by the edge of the petal[2] Pearson M., Generative Art, Mannig, 2011.

of a flower. Petal of the flower is basically presented as a[3] Kolarević B., Half Cadence: Towards Integrative Design,

single wing of pavilion and edges of Voronoi petal witch

Proceedings of CAADence in Architecture, University ofmatch the center of the flower is continuing smoothly into

Techology and Economics, Budapest, pp.27-31, 2016.

the pillars. In this way, the structural differences between the[4] Čučaković A., Jović B., Komnenov M., Biometic Geo-

petals and pillar are invisible crossed. Modeling of the object

metric Approach to Generative Design, Periodica Poly-is basically derived by generating surface of wing-petals andtechnica Architecture, University of Techology and Eco-

pillars obtained by sweep command based on the rail

nomics, Budapest, pp.70-74, 2016.
[5] Šilić Č., Endemične biljke, Svjetlost - Zavod za

represented by manually defined curve. In order to obtain audžbenikei nastana sredstva, 1987.

final solution, or to set the thickness of the structure, surfaces
are offset to a specific thickness. The final model of pavilion[6] Jović B., Tripković M., Čučaković A., Geometric corre-that corresponds to a structure of the flower, was obtained bylation of cultural landscape patterns and Prunus Domes-

petals that are repeated 4 times in a circular arrangement.

tica L., Glasnik Šumarskog Fakulteta, Šumarski Fakultet,

The resulting model is designed as a landscape-architecturalVol.104, pp.29-40, 2011.
[7] Leopold C., Folding structures, A hermit’s cabin, Eras-

installations in the space.

mus intensive programme Kaiserslautern, Structural Ar-

3 Software & System

chitectures – Geometry, Code and design II, Technische

The model is done in system with performances of 2.4 GHz

Universitat Kaiserslautern, pp.18-20, 2013.

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3D-Materials for Mechanical Design and Drawing Education--Technical Assistance Through Experience
Tsutomu Araki

Tsutomu Araki “3D-Materials for Mechanical Design and Drawing Education --Technical Assistance Through Experience” 2017, Material: VeroWhite, Size: 55W x 53D x 10H (mm)This is a collection of teaching materials for mechanical modeling, intended to deepen the students’ thinking, encourage criticalassessment, and enhance their capabilities in creating the best products through the educational application of machine designing/drawing and computer-aided design. We encourage our students to comprehensively experience and be educated by use of thesematerials for learning technical drawing, through user experience evaluation of student-designed shapes and functions, and trial
production of blocks to learn about the processing accuracy or characteristics of 3D modeling machines. These are selected examplesof our methods for supporting design and drafting education at our university.

42

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Keywords: Teaching materials, Materials for drawing method, Hands-on experiences, Consciousness of modeling accuracy, Hints for
3D-modeling, Optimization

1 Materials for students to deepen their thought
through hands-on experiences
Tsukuba University of Technology (NTUT) is the only higher
educational institute for the hearing or visually impaired inJapan. In the Mechanical Engineering Course, we educate
Figure 2: Hand winch’s handle lever (Left, in a red circle), Students’ design for hand winch’s Ratchet wheel (Right)

hearing-impaired students. And we educate with emphasis
on Mechanical Design and Drawing because students with anengineering education typically go on to join a company
where they are involved in design and CAD. Tsukuba
University of Technology (NTUT) introduced an inkjet type3D-modeling machine in 2007. Since then, we have beenusing the machine for the education of design drawing, andcollecting data on experience and knowhow for effective use.

Figure 3: Handle lever R1 model, Exhibition stand and pin

Utilization of 3D-CAD and 3D-modeling at our university is

grip condition of each fillet.

a means of motivation and communication for high quality

Teaching materials to try and feel in one’s own hands.

design and drafting education for hearing-impaired students.

Students will be able to optimize their mechanical design.

The model introduced here is part of the teaching materials

One of the small stacks to improve one’s own sense offor the development of education.

design.

2 Works of 3D-model as teaching materials

2-2 M20 Teaching materials of Bolt screw: 3D-model for

2-1 Handle lever: Teaching material of function of lever

Exercises on Machine Design Drawing and Practice of Manufacturing Processes as a Teaching material.

Figure 1: Aseenbled handle levers FILLET R0, R1, R2, R3, R4,
R5 on a Exhibition stand (Left side), Usage of a handle lever for
Ratchet wheel of Hand winch (Right side)

Figure 4: M20 Bolt as a Teaching Material

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When producing with a 3D-modeling machine output at

2-4 Materials for teaching of drawing: Teaching materials

200%.

to show how to draw in the same form as the diagrams oftextbooks and to gain a better understanding.

2-3 Projection teaching material: projection drawing method

Produced as a model to use for explanation of drawing.

Teaching material for explanation of projection method.
Made with transparent material. You can see the same
explanatory symbol as in the textbook on each side.

Figure 8: Teaching materials 3D-CAD data for simplified drawing example of intersection same as text bookFigure 5: 3D-CAD data, Size: 40W x 30D x 50H (mm) and 3Dmodeling (Right side), Figure from textbook (middle side)

Figure 6: Figure from textbook

Figure 9: Simplified drawing example of intersection, figure
from textbook

Figure 7: Easy to produce by 3D PrinterFigure 10: Eyebolt, 3D-CAD data and figure from textbook

44

Finalista.

Models for consciousness of modeling accuracy of
3D-modeling machines

Shafts and bearings are often used for precision mechanism
models. Regarding to the dimensional accuracy: It is important to compare the dimensions of the drawing data of length,
width and height with the actual size of the height, width andheight of the 3D-model, and to know the machining accuracy
Figure 11: Chuck Handle, 3D-CAD data (assembled data andparts) and figure from textbookof the 3D-machine. When manufacturing a cylinder (shaft)A model for showing the same shape as the drafting sample

the machining dimensional accuracy of the 3D-machine byof the textbook.

horizontal placement and vertical placement.

Even if the real standard of the same standard exists in the

These are models for consciousness of modeling accuracy offactory, it is often different from the form of the drawing

3D-modeling machines.

or a perfect circle (bearing) by 3D-modeling machine, checkmodel of the drawing textbook.
For example; “Eyebolt”, “Chuck Handle”.
2-5 Assembling on the 3D-CAD monitor / Assembling realparts by 3D-modeling machine: Experiencing assembling
on a monitor of 3D-CAD and assembling real parts which

Figure 12: Test pieces by 3D-CAD data and 3D-modeling φ25 x
50W x 50D x 50H (mm)are made by 3D-modeling machine.
Insert a shaft of diameter 10 mm into a diameter 10 mm hole.

b.

Although parts can be assembled on the monitor of 3D-CAD,

Model for the possibility of shaping --Performancethe producted axis by this size does not enter the hole in the

check: Precise forming for 3D-machine and Deform-

real model of this size. Please try it.

ing for materials ( φ1, φ2, φ3, 50mm(H) )Whether precise shaping is possible at a height of 50 mm

You will be able to recognize that it is necessary to think
about dimensional tolerance for the machine design.

2-6 Considering that it is made with a 3D-modelingmachine according to 3D-CAD drawing data: Test
pieces for effective useage of 3D printer features
Awareness of processing.
Consciousness of modeling accuracy.

Figure 13: φ1, φ2, φ3 x 50H(mm), φ1_3D-modeling45

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with a diameter of 1 mm. It may be deformed with the passage of time due to the shaped material. For our 3D modeling machine and materials, we can shape them. However, inthe case of a 1 mm diameter pillar, it bent after making it.
Figure 16: Size 10%: 22W x 10D x 9H (mm), (Left side) Size
30%, 20%, 10% model, (Right side)

2-7 A model offers the possibility of manufacturing
as an industrial product, even though it can be madewith a 3D- modeling machine

the bottom of the car that is under the shaft.
Devices for removing support agent that fills the gap forturning the axle and hole tire with jet water stream.
Precise model of one sample of small 3D-modeling; it can be
low cost material and therefore easy to share.

3 Usage of the New Method to Make Specimen for
Photoelastic Test
It was found that a 3D-modeling machine can easily produce

Figure 14: 3D-CAD data (L) and 3D inkjet modeling figure (R)specimens for photoelastic tests. Any shapes of specimens

2-8 A model that allows you to think about devisingwhen making with 3D-modeling (a model thatmakes you think of the necessity of ingenuity)

can be produced based on a 3D-CAD drawing, as if theyGood model for PR-Car use.

is a simplified one made of a tracing stand furnished with

Precise model as one sample of 3D-modeling for it can be

LED plate illumination of white light shining on thecheap.

specimen from behind. As students got more familiar with--- Scale: Output size 10% of 3D-CAD modeling data (maketests, the items they need to consider in design increased

were printed by a printer. This enabled us to implement
photoelastic tests without difficulty. The apparatus used here

it easy to draw output with the desired percentage size).
Make a slit to remove support agent with jet water stream at

Figure 17: 3D-modeling machine can easily produce specimens
for photoelastic tests. With notch at the upper part and stressconcentration can be seen (Right side), none (Left side)

Figure 15: Good model for PR-Car use; tire axle also rotate

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Figure 18: Photoelastic tests with notch and none (Left side),With notch inside the photoelastic test (Right side)much more. We expect to have further opportunities todevelop new areas of the utilization of CAE including
3D-CAD and 3D-modeling.

Figure 19: As a teaching material to make sense of modeling experience in one class period “Making a mini-hanko”

Various shapes and notches can be made freely. I believethat the scope of further utilization will expand as a teaching
Modeling Machine which offers a chance to think and try do-

own interest, we hope students can get a hold of theing by ourselves.

techniques of technical design drawing and CAD usage
positively.

4 The first 3D-CAD experience teaching material atour university

5 Software & System--Making a mini-hanko (personal stamp): Basic 3D-CAD

Software: Autodesk Inventor

operations and 3D RP modeling

Modeling machine: Objet EDEN260, inkjet modeling ma-

Manipulation of 3D-CAD and production of 3D-model usingchine

mini-stick teaching materials. As a teaching material to
make sense of modeling experience in one class period

References“Making a mini-hanko”. Hanko means one’s own name[1] Araki, T., Nakamura, N., Honma, I., Educational Assis-

stamp.

tance Through Modeling in Tsukuba University of Tech-

Through the making of a mini-hanko by 3D-CAD and 3D RP

nology--Professional Education for the Hearing or Visu-modeling, students can learn about the basic operations ofally Impaired, Computer Aided Drafting, Design and

3D-CAD, as well as the development flow from data drawing

Manufacturing (CADDM), China Graphics Society,to manufacture. Of course, using and trying is real modeling.

Vol.25, No.4, pp.58-65, 2015.

Production costs are low, production time is short. The pro-[2] Araki, T., Hirano, S., Development of cooperative educa-

duction of a strapped mini-hanko that students can actuallytion and basic engineering education: aided by 3D CAD

use afterwards serves as a summary of the basics of CAD.

and 3D RP modelling, Int. J. Computer Applications in

By guiding students through a production process of theirTechnology, Vol.51, No.1, pp.80-85, 201547

Report on How to Construct 3D Models for 3D PrintingReport on How to Construct 3D Models for 3D Printing
Misako Nishii, Yoshiaki Machida1.

Foreword

shapes (called polygons or faces), the model must be aThis report discusses digital modeling methods for printing

polyhedron with one space.

data analyzed in past Digital Modeling Contests using 3D

If the 3D model data to be printed is one of the following

printers.

polygons, error will result in most cases and the data cannot

Each year, the works entered into the Digital Modelingbe printed, although it may differ according to the mechanism

Contest held since 2008 become more and more elaborate.

of the 3D printer used. Such data must therefore be corrected

To construct such elaborate models, applicants are required

first. Some modeling software are provided with functions toto submit high quality model data appropriate for the

check the quality of 3D model data or correct errors

modeling machine to be used in the contest. In order toautomatically. These functions can resolve errors to a certain

enhance the quality of the model data submitted, the sponsor

extent, but when these functions are not available, generally

provides information on the characteristics of the specifiedediting software for STL data are used.

modeling machine and how to use the machine in the contest.

There are also methods for correcting errors by hand, but

Since the applicant and sponsor need to mutually understandthey can only be applied if the user understands the errors

the importance of data quality, the sponsor verifies whether

correctly and have the skills to carry out the appropriate

the data of works entered is suitable for printing, and informs

procedure. Again, these methods are complicated and take a

the results to the applicants. During the verification, thelong time. Based on the results of data verification functions

executive committee and members repeatedly verifyies

and data analyses obtained to date, possible causes of errors

various issues with the cooperation of the manufacturers ofand preventive measures are discussed in the following.

3D printers.
For digital modeling data that needs to be output using 3D(1) 3D model data must be a polyhedron with one closed

printers, there are three important steps in the modelingspaceprocess. They are “3D shape modeling”, “data conversion”,<Causes of errors>and “output”. The keypoints of each step are as follows.

· Presence of thin polygon· Presence of hole (opening)2.

Keypoints in 3D Shape Modeling· Part of polygon is protruded

The intermediate file format most commonly used when

For the first cause for error above which is the presence ofprinting 3D model data with 3D printers is STL

thin polygons, this may occur when modeling software(stereolithography). When using the STL format for printing

generally called “polygon modeler” is used in CG“polygon models” which consist of continuous triangular

production. This modeler is able to create three-dimensional

51

shapes by joining polygons. Polygons are not thick. If all

to each object, and integrate the multiple free-form surfaces

polygons are connected, they form a state with no thickness

with thickness.

like a piece of paper. This state with no thickness does not

The second cause of error is the lack of polygon (fig.2) or

influence the CG production, but causes errors when printed

the normal direction of the polygon is facing the opposite

with 3D printers (fig.1). For example, when modeling

direction if there are holes (openings). There must be no

figures, even areas which do not require thickness in CG

holes at all in the data. First, there is a need to see if thesuch as hairstyle, sleeve and hem of clothing, etc., need to be

problem can be resolved by setting the normal of all

given thickness when modeled and printed with 3D printers.

polygons to the same direction using the modeling software

The same applies for numerical visualization techniques

repair tool. If holes remain, they have to be closed. Someand informatics. Spatial curved surfaces automatically

software programs have functions which automatically close

generated by software programs must also be given thickthe holes. The names of these programs are not disclosed

geometries in the same way. Without thickness, there will

here as they can only be used in limited environments.

first be a need to import the data to a modeling software to
add the thickness. One method of resolving this would be touse the extrusion method when dealing with simple freeform surfaces. However, when dealing with an integrated
geometry consisting of multiple free-form surfaces
intersecting each other, it is not easy to add thickness to theintersecting areas. There would be a need to import eachindependent object to the modeling software, add thickness

Figure 2: Presence of hole (opening)

The third cause of error is difficult to correct by automatic
correction for polygons with ridges that are protruded (fig.3).
There is a need to edit the object by hand while checking theshape.
(2) Boolean combination<Causes of errors>
When polyhedron 1 and polyhedron 2 overlap, a third

Figure 1: Presence of thin polygon

52

Figure 3: Part of polygon is protruded

Figure 4: Two polygon objects

polyhedron 3 is formed in the STL data (Fig.4) .
Errors tend to occur easily when some polygons areoverlapping (interfering) in structures made up of multiple
polyhedrons. The first cause of error is geometries composedof balls piled above balls like a snowman. The existence ofmultiple divided spaces in areas that are overlapping, is notallowed in data (Fig.5). Polyhedrons need to be single
structures called “shell” by using Boolean connection to join

Figure 5: An overlapping area exists in two objects.

multiple polygons (Fig.6). In the case of the snowman, thisprocess removes the partition between the two balls to
become one snowman-like polyhedron.
(3) Duplicate operation of objects to be appropriate for 3D
printers.
<Causes of errors>
In this case, parts are continuously copied to create the 3Dmodel data. But STL data does not support copied
geometries. In modeling, parts are sometimes copied andused. In some cases, to lighten the data, the geometry of the

Figure 6: Using Boolean connection to join multiple polygons

53

parts itself is not copied, but models of parts are copied by aprinting out the data directly, there is a need to test somemethod called “instance”. When data is copied, it isparts of the shape.

substantial and tangible, however in the case of the instanceThis contest provides information on the type of 3D printermethod, because the original object itself is not copied but

used and clearance specifications at the time entries are

only referenced, the data is not substantial. When such data

invited based on past results.

is directly written to STL, geometry information will not bereflected in the instance. Thus, there is a need to first convert(6) Object tolerance (Deviation)

instance to actual object before writing.

<Causes of errors>· When tolerance is large, the modeled geometry is rough.

(4) Degree to which object surface is divided.

· When tolerance setting is inappropriate between the two

When modeling by CG production and rendering is carriedsystems used, error occurs.

out, the geometry is made smooth by this rendering, and not· When tolerance is too small, the STL data file size is

by using polygons. When printing with 3D printers, as theexcessively large.

data is printed based on the number of divisions of thepolygon models, in order to convert it to the STL format,

As mentioned earlier, there are various 3D CAD data

there is a need to increase the number of divisions of theformats. In order to carry out laminate molding using 3D

surface as required.

printers, data must first be rewritten to a triangular aggregate,
and printed in the STL format. At this time, there is a need to(5) Adjustment of clearance by part

specify how many polygons to divide the 3D model data

<Causes of errors>

into. This is called “tolerance”. There are several kinds of· Some models can be printed out in the assembled state,

tolerance, here we will introduce caution points in CAD.

but cannot be moved because the clearance is too tight.

Tolerance is proportional to the distance between· The model data of some models created by parts expan-

triangular vertices. The smaller this value, the more detailed

sion can be output, but the fitted part is narrow and parts

will the geometry be, On the other hand, the larger this value,cannot be assembled.

the rougher will the geometry be. Tolerance is set not only
using the data converted, but on all systems handling the 3D

In the design of the mechanisms of industrial products, there

data such as laminating machines. When the data value andis a need to design the clearance according to thevalue of the settings on the laminating machine differ

characteristics of the resin used and the shape of the productconsiderably, error may occur. Thus, there is a need to set themodeled. Even if a data has been printed out before, thatdata and laminating machine setting to more or less the sameclearance is often inappropriate on a different 3D printer andvalue. In this contest, entries are recommended to set theneeds to be adjusted each time it is printed. Instead oftolerance to 0.005 mm to 0.01 mm.

54

The following are example, how to set tolerance by
converting CAD file to STL format when using StratasysTM
3D printing system.
These sentences are quoted from Objet260 user guideDOC-37004 Rev. E[1].
The following instructions generally apply for this printer.
This procedure may vary slightly depending on the CAD
software used.
When value is large Geometry When value is small Geometry
is fineis rough

To convert a file to STL format (in a CAD program):
1. From the File menu, select Save As.
2. In the Save As dialog box, open the Save As pull-downmenu and select Save As. “STL”.

Next, an example of a typical error is shown. For instance,

3. Click Options and set the following parameters:

when there is data in which the tolerance is set to a large

Total Quality- approximately 0.01 mm (deviation toler-value(for example 0.5 mm), and the laminating machine isance / linear-dimension tolerance)

set to a high precision (for example 0.005 mm), increasing

Detail Quality- approximately 5° (angle tolerance)

the numerical precision of 3D data will also increase the data

Note: Lowering these values produces more accurate

volume, therefore attempts are made to set the tolerance to amodels, but results in larger files and longer loading andlarge value. This means that a large value has to be set for theprocessing times. For this reason, it is generally not rec-reference (threshold) for judging the error between surfaces.

ommended that you use lower values.

By reading this data on a system set to strict error judgment

4. In the file format option, choose binary or ASCII. (Bothsettings, an enormous number of errors will occur. If thebinary and ASCII formats can be used in Objet Studio.

tolerance is set to 0.005 mm for instance, as long as the

However, binary files are smaller, so this option is recom-

distance between the surfaces composing the polyhedron ismended.)large, it is judged that the surfaces are apart from each other.

5. Click OK or Save.

Consequently, this is judged as a hole, and error results. This

After converting the model files, it is recommended thaterror occurred with a laminating system set to a highyou check them for defects in an STL-repair application

precision (for instance 0.005 mm) and will not occur with(such as MagicsTM, by Materialise®)laminating machines set to loose settings. This means when

before opening them in Objet Studio and producing theattempts are made to find and correct errors in data createdmodel.

on one’s own PC (loose settings) in another similar
environment set to the same loose settings, they cannot be

55

found. To correct such errors, the tolerance at the laminating

magnified state will not be known. In CG production, size ismachine should be set loosely (for example 0.5 mm). But

not given significant attention, but due to such problem

this method is not ideal as the data quality drops significantly,

occurring, the user needs to take into account the size andresulting in the modeling of rough geometries.

unit of the model data.

One method of resolving errors without sacrificing data
quality would be to use the “stitch” function for joining

3.

Data Conversion

surfaces. This function is provided with editing software and

The main modeling software type differs according to thepresently used mainly for correcting STL data.

field used in: CG production and design. In some cases, thetechniques for configuring geometries created using different(7) Model size is very small after conversion to STL data

software programs differ. Intermediate file formats often used

Units are not inherited in STL format. As a result, the overall

and the areas in which they are used are introduced below.

size of the model may become very small, below 1mm. In
this case, it can be changed to the appropriate size with thesoftware of the 3D printer. However, if the object iscomposed of several parts, the appropriate clearance in theFormatType of main geometry Remarks

Field in which this file format
is mainly used

OBJ

PolygonMay be included in formats which can be read by 3D printers

3D CG

STL

PolygonStandard intermediate file format for 3D printers

3D CAD,3D CG

IGES

Surface

File format for CAD data exchange created by the American National
Standards Institute(ANSI).

3D CAD,3D CG

STEP

Solid

File format for CAD data created by the International Organization forStandardization(ISO).

3D CAD

XVL

Polygon/Surface/Solid Lightweight 3D file format developed by Lattice Technology Co., Ltd..
3D data is used for design, manufacturing, parts procurement service,etc.

WEB 3D,3D CAD

DXF

Surface/Polygon

3D CAD

2D intermediate file format is the most known intermediate film format.
But there also exists intermediate file formats for 3D modeling. 3DCAD
data may be used for reading.

56

4.

Reviews Issues when Printing with 3D Printers4.1. Relation between Modeling Time Efficiency and
Output Model(1) Geometries which can be improved by dividing andassembling
By dividing the geometry and printing it, the printing time
can be reduced.
Figures 6 and 7 show a model designed by mathematicalFigure 6: When modeling
Original Object data: Kiyoe Fuchigami

modeling being divided at a uniform height, modeled, andassembled. Normally, modeling is carried out in theassembled state, but with models that are tall and havevolume, modeling time and material costs will increase andsupporter to one-third, and modeling costs to 1/3.

become costly.

Figure 8 shows an example of a model constructed fromIn this case, the model is divided horizontally, parts aredesign data already assembled. Assembly is not carried out

overlapped and modeled as shown in Figure 6 As a result, theafter modeling. Only post-processing such as removal of theheight could be reduced to one-sixth, the volume of the

supporter etc. is carried out. The 12 gears incorporated in the

Figure 7: When assembling
Original Object data: Kiyoe Fuchigami

Figure 8: Assembled model
Object data: Stratasys Ltd

57

model could all engage with each other and move.

With this work, removal of the support was thought to be

The base, frame, and gear are built separately, anddifficult, so we asked the creator of the work to correct theassembled at last. This is the same procedure as conventional

thickness of the face to about 2mm.

modeling methods, but because the assembly is done by

Most of the other entries were elaborate and easy to break.

hand, it takes considerable time and efforts. The model in

Many used supports which could be removed by chemicals.

Figure 8 does not require any efforts at all to assemble.

Still it was difficult to remove the supports safely, and someof the 11 finalist works had to be remolded due to failure to

4.2. Problem of Removing Support in Modelingremove the supports. In this way, the safe removal of

The work for removing the support is also an important step,

supports is a common problem shared by manufacturers.

and precautions to be taken in the removal are described

Manufacturers are therefore presently developing various

below using some examples.

types of support materials, and users are still in the midst of

As new 3D printers continue to be released one after thefinding appropriate support materials. Understanding theother, laminated molding (additive manufacturing) can now

characteristics of these materials and learning how to remove

be carried out in detail. On the contrary, this has made itsupports safely and accurately will continue to be a challenge

increasingly difficult to remove the support without breaking

in the future.

the laminated model.
5.

For example, thin lines (cylindrical columns) of about 0.1

Instructions on Preparation of Entries and Precautions in Data Creation

mm in thickness can be output for ink jet (polijet) machines,
but because the water used for removing the support is

In ADMC2017 and Digital Modeling Contests until now,

injected out at high pressure, the molded model may be“Instructions on Preparation of Entries and Precautions on

deformed by shredding, etc.

Data Creation” were provided for the preparation of models

Of the 11 finalist works of this contest, all the faces of one

using the modeling machine “Eden260VS”. Specificationsof them were about 0.2 mm thick. At some areas of theare shown below.

structure, the thickness was less than 0.1 mm thick. The
6.

results of data verification confirmed that the structure can be

Type of Resin Used, Amount Used, and Printing
Time in Printing of Entries

molded by normal methods. Faces which are about 0.2mm
thick are thought to break easily when the support is

The following shows the resin amount used and printing time

removed. For such shapes, water soluble supports may beof a finalist entry of this contest using the 3D printerused to remove them without applying high pressure water“Eden260VS”.

currents. The support material of the molded model absorbs

As the support material is disposed after printing, it iswater and expands, and this may cause the problem of thepreferable that the amount of material used is small. For

molded model becoming deformed according to the shape.

cases where the support material used is considerably more58

Entry1

DualityResin for modelingType
VeroWhite

Support resin

Amount (g)TypeAmount (g)257

SUP7072,465

Output time (h)
17:49

2

Chladni Towers

VeroWhite

421

SUP707

897

8:56

3

Pre-programmed deformable material

VeroWhite

162

SUP707

206

1:31

4

Capricious Hearts

RGD720874

SUP705

1,166

8:10

5

3D PRINTED MODEL AS AUGMENTEDREALITY MARKER

VeroWhite

2,174

SUP707

2,696

27:26

6

Design by Spheres – A Project for Museum

VeroClear

1,993

SUP707

2,194

18:01

7

OJIGI TOKURI (Self-Tilting Sake Bottle)

VeroWhite

186

SUP707

585

7:21

8

Design lamp shade

VeroClear

804

SUP707

1,644

14:53

9

Triskelion Blocks

VeroCyan
VeroMagenta
VeroYellow

138
359
372

SUP705

94

6:30

10

Natalie’s Ramonda pavilion

VeroWhite

454

SUP707

1,289

21:05

11

3D-Materials for Mechanical Design andDrawing Education--Technical AssistanceThrough Experience

VeroWhite

15

SUP70725

0:40

3D printing partner company: ALTECH Co., Ltd., (2,3,4,5,10,11), Stratasys Japan Co.,Ltd., (1,6,7,8,9)

than the amount of resin used for the model, there is a need

Reference

to consider printing methods which can reduce the amount of[1] Stratasys Ltd. “Objet260 User Guide DOC-37004 Rev.
E”, p3-9.

support material used by dividing the model and building it.

59