3D Pen + 3D Printer : Exploring the Role of Humans
and Fabrication Machines in Creative Making
Haruki Takahashi
Meiji University
Nakano, Tokyo
haruki@meiji.ac.jp

Jeeeun Kim
University of Colorado Boulder
Boulder, Colorado
jeeeun.kim@colorado.edu

ABSTRACT1

The emergence of a 3D pen brings 3D modeling from a screenbased computer-aided design (CAD) system and 3D printing
to direct and rapid crafting by 3D doodling. However, 3D
doodling remains challenging, requiring craft skills to rapidly
express an idea, which is critical in creative making. We
explore a new process of 3D modeling using 3D pen + 3D
printer. Our pilot study shows that users need support to
reduce the number of non-creative tasks to explore a wide
design strategy. With the opportunity to invent a new 3Dmodeling process that needs to incorporate both a pen andprinter, we propose techniques and a system that empowerusers to print while doodling to focus on creative exploration.
Our user study shows that users can create diverse 3D models
using a pen and printer. We discuss the roles of the humanand fabrication machine for the future of fabrication.

With the rise of personal fabrication and affordable digital
fabrication machines [3, 24], CAD tools and creativity support [34] have become challenging themes in the HCI field.
Despite advances in 3D printing, users’ creative activities
for creating 3D objects have been limited. To lower the entry barrier for users, most general-purpose CAD tools haveusers work from shape primitives or spline systems, which
unwillingly induce a procedural process.
At present, commodity 3D pens are largely available. A
hand-held 3D printer allows users to directly manipulate
3D shapes on-the-fly without any digital 3D models readyfor processing and to modify the modeling process as they
make things using craft materials. Nonetheless, 3D doodlingalso remains a challenging task and requires craft skills toconstruct a plausible 3D shape. Existing studies propose
the use of stencils [1] or mixed-reality guides [45], thereby
leaving space for CAD at some points. We aim to extend
these studies to the next step and enable users to directly
manipulate 3D objects in the creation process.
In this paper, we discuss the challenges and opportunities
for creative activities using a 3D pen and examine what typeof making experiences can be realized to empower users to
explore creative making with 3D printing. Currently, a 3D
creation bipolarizes modeling into a screen-based design anda challenging but creative hands-on activity. Our motivation
is to explore the capability of 3D pen + 3D printer around ahuman’s creative activity to encourage the use of a 3D pen
in modeling.
Our key contributions are three-fold:

CCS CONCEPTS• Human-centered computing → Human computer interaction (HCI);KEYWORDS
Digital fabrication, 3D pen, 3D printer, creativity
ACM Reference Format:
Haruki Takahashi and Jeeeun Kim. 2019. 3D Pen + 3D Printer :Exploring the Role of Humans and Fabrication Machines in Creative Making. In CHI Conference on Human Factors in Computing
Systems Proceedings (CHI 2019), May 4–9, 2019, Glasgow, Scotland
Uk. ACM, New York, NY, USA, 12 pages. https://doi.org/10.1145/
3290605.3300525
Permission to make digital or hard copies of all or part of this work forpersonal or classroom use is granted without fee provided that copies are notmade or distributed for profit or commercial advantage and that copies bear
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permissions from permissions@acm.org.
CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk© 2019 Association for Computing Machinery.
ACM ISBN 978-1-4503-5970-2/19/05. . . $15.00
https://doi.org/10.1145/3290605.3300525

INTRODUCTION• Identification of the key factors in creative making with apilot study of general 3D pen tasks. Introduction of a 3D
printer into 3D doodling as a tool to facilitate creativity.
• Seven design techniques to facilitate creative making experiences using pen + printer. Workflows with a 3D printersetting and a system that allows users to print simple
shapes that can serve as scaffolding for creations.
• A user study that shows a new opportunity for using pen+ printer in creative making. A variety of craft techniquesand strategies that involve the use of a 3D pen and 3D
printer in creative ways.

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2

RELATED WORK

Our work is inspired by personal fabrication with a focus on
supporting hand work using digital fabrication technologies
by investigating the unique roles of these two participants.
Personal & Digital fabrication
Recent research on personal and digital fabrication moved
the focus to improve efficiency and interactivity in the design process [5, 8–10, 25, 26, 28, 37]. With the concept ofinteractive fabrication [43], recent advances in this domain
have facilitated the real-time input for fabricating physicalforms and allowed humans to directly manipulate machines
throughout their processes [27, 29, 30, 41, 44]. The basis of
our work originates from this lineage of work in facilitating
direct manipulation and interactive fabrication by exploringa new type of personal fabrication to present unique workflows by combining digital fabrication and craftsmanship.
Support for Hand Work by Digital Fabrication
Hand-held craft tools offer a hands-on fabrication experienceand support quick exploration [49]. D-coil [31] and FreeD[47] add intelligence to a device and assist designers withhaptic feedback according to a design input. ExoSkin [15]helps on-body fabrication using a human body as a canvas
to explore hybrid fabrication workflows. SPATA [40] is asmart tool that enables a designer to measure and transfer aphysical dimension to synchronize hand work the digital design. WeaveMesh [36] is a prototyping system that produces
objects in a mesh structure inspired by the craft of handweaving. Using clay and printed widgets, “What you sculpt
is what you get”[19] allows a designer to make interactive
devices without requiring skill in a CAD system. 3D pens,
one type of hand-held device, still require support [45]. We
identify the key factors in creative making with general 3D
tasks and introduce a 3D printer to 3D doodling as a support
tool to facilitate making.
Collaborative Digital Fabrication
Collaborative and social fabrication has provided a promising
future for fabrication [3]. The latest work proposes machines
to be used as a tool during creative works, not simply as
the final output appliance. For humans to collaborate withmachines as co-designers, machines should be thought ofas live collaborators and agents to aid in-situ creativity [20].
Similary, compositional 3D printing [22] recasts a fabrication
process to enable users to compose a 3D model via realtime design decisions and expressions. Hybrid fabricationis the vision of integrating digital fabrication techniqueswith analog craft practice to extend traditional craft. Hybrid
artisans [48] have examined the value added to traditional
craft practices. To facilitate both high-fidelity crafting and

Takahashi and Kiminteraction with materials, Proxyprint [39] and MixFab [42]invite users to bring existing objects and materials to a digital
design space. Being the Machine [14] proposes machines as
guides for users to reconfigure agency and control in hybridfabrication. However, collaborative fabrication systems lacksupport for users while making as needed during the process.
We adapt previous work to promote collaboration between
machines and humans [7] but in an advanced manner tofacilitate more creative ways of 3D creations.
3

3D PEN + 3D PRINTER

Motivation and Goal of 3D Creation
For a pilot study, we first suppose three types of motivationand strategies of 3D creation while comparing the role ofhand work using a 3D pen with 3D printing.
(A) With a concrete goal, making with high fidelity
Proceeding toward a clear goal is one creative experience[12]. In this motivation, users may expect an outcome withhigh fidelity and expressiveness. If there is a 3D model as agoal and users have sufficient knowledge, that will be thegoal. In creative making using pen + printer, for example,
a 3D printer can contribute to users by accurately printing
complex shapes, smooth surfaces, and almost anything withfidelity with regard to the physical properties such as size,
symmetry, and proportion.
(B) Deciding what to make while making
This is similar to many creative activities in which humans
explore what to create and how to create while actually making it. Like sketching in the early stage of creation [6], a 3D
pen also welcomes this type of motivation. It is importantfor users to rapidly explore various possibilities and engage
in creation. A 3D printer may not work well at this stage
because it requires a 3D model, but it can be used as a tool
to explore or partially create a goal. For example, a user who
wants to create any animal (but has not decided which animal) can print a snowman-like shape as a scaffold for 3D
doodling and can explore by adding ears, limbs, and a tail.
(C) Without a goal, just making, playing, and learning
A 3D pen allows users to manipulate shapes without any
digital 3D models; therefore, users can start making withouta goal. Users can not only explore but also positively engage
in the activity and enjoy it. Hopefully, an understanding ofmaterials will be cultivated through work [14]; serendipity
due to manual uncertainty will be added to the work. To clarify a goal, a 3D printer can contribute by printing examples
or almost completed objects; these allow users to explore
and easily reach a goal.
Pilot Study: User’s Goal Setting and Reaching
Taking into account the three premises, we conducted two
pilot studies to understand how users handle a 3D pen, what

3D Pen + 3D Printer

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk

Figure 2: 3D doodling techniques: (a) conventional wiredrawing, (b) doodling using stencils, and (c) doodling using
a foreign item. We consider doodling with a printed object.
Figure 1: Pilot study. (a) Two participants attempt to doodle
simple primitives. (b) Some high school students try wiredrawing. (c) Students doodle with 3D printed objects.

difficulties they may face, and what opportunities are available for new types of 3D creation processes. The purpose of
the study is observational; we recruited two graduate students from the lab and a group of casual users including somehigh school students regardless of their prior experience. We
only explained how to use 3D pens and let them freely workwithout any restrictions. We prepared 3D pens, craft tools,
and example objects. To save time for 3D printing during thepilot study, we prepared preprinted craft scaffolds.
We instructed the two participants with no experience
with 3D doodling to make simple primitives using a 3D pen
and craft tools for an hour (Figure 1a). We let them makesolid shape objects and provided example objects, so thatthe participants can have a concrete goal to achieve (A).
Similarly, we asked the casual users to use a 3D pen without
providing specific instructions. Some participants seemed
to have a vague goal (B), and they stated what they would
try to create, e.g., a wireframe box, a cylinder, and their own
name (Figure 1b). Some participants who started to doodle
without saying anything seemed to not have any goals (C).
We observed that the participants enjoyed doodling, andvarious ideas were rapidly physicalized. They exploited craft
tools in various ways to leverage creations (Figure 1a); one
participant used a spatula as a wall to support doodling, while
another used a tweezer as a spindle to wind material. The
casual users also engaged in 3D doodling, and some of themcompared the 3D pen to a glue gun. However, they wereunable to doodle even simple primitives or created unstablewire shapes, as reported in [45].
Towards Creative Making with Pen + PrinterWe found that a 3D pen allows users (1) to directly manipulate material and experience rapid physical making, often(2) letting users enjoy the process— critical factors for creative exploration. Similar to crafting, humans can have more
control of the object, even without concrete goals at the beginning. However, without proper support, users may havedifficulties reaching the goal of making, and the variety could
be also limited (Figure 2a). Inevitably, human skills lack precision and speed. With the rise of 3D doodling, stencils havebeen provided by designers to support beginners [1]. Users
only need to follow fixed lines in 2D, transform it, and assemble an object into a 3D shape. If they weld parts, somewhat
sophisticated objects can be created (Figure 2b). Skilled users
often utilize craft materials; for example, crumpled paper
can be used as a scaffold to obtain a global shape (Figure2c). Users can then be more concerned about other factors
to enrich their design: color, texture, size, and more. Thus,
users can improvise further and create personalized objects.
It is important for users to understand how to distribute aload associated with a creative activity [13].
We envision offloading non-creative work to a 3D printer.
Figure 1c shows the creations made by the participants. We
provided printed objects such as animals, a tree, and a nameplate, and the users decorated them using a 3D pen. They
were able to create varieties that are unique to each otherby only stroking the surface of the object. As observed in[39], users can be at the correct stage where they need theirown creativity. The power of a 3D printer, however, may
deprive the user of serendipity, ownership, a sense of accomplishment in 3D doodling. With these motivations, we
introduce and demonstrate design techniques and presenta system that allows users to 3D print what they can use
during creation while doodling their 3D objects.
4

DESIGN TECHNIQUES: DOODLING + PRINTING

In this section, we introduce seven design techniques that
innovate the 3D modeling process using a 3D pen and 3D
printer. We first categorized the keywords found from thepilot study observations of users’ behaviors, previous works,
and collected use cases including 3D doodler’s how-to videos,
art works showcased on Pinterest, and YouTube videos.1 We
subsequently derived categories for these techniques.
Technique 1: Adding details to a 3D printed body
As observed in the pilot study, even creating a simple primitive could be challenging. In this case, users can benefit from
1 We gathered contents with queries such as 3D pen and 3D doodling

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk

Takahashi and Kim

Figure 4: Comparison of textures made with a 3D pen, a 3D
printer, and 3D printing techniques.

Figure 3: 3D doodling on 3D printed objects. (a) Users can
produce works by stroking the surface or (b) filling wireframe structures using a 3D pen.

precise 3D printed scaffolds that operate as guides for novice
users. Complex shapes such as animal bodies can also be
printed for 3D doodled details (Figure 3a). Users can easily
reach their concrete goal, being able to care only about details or addenda (i.e., the surfaces of soccer balls, the leaves
on trees, and the hairs on animals). However, the users’ spaceof creative exploration is limited, as they may largely rely
on a global shape. For example, creating a giraffe from a lion
would be nearly at impossible, while adding lion hairs todecorate the animal figurine is relatively easy to accomplish.
Technique 2: 3D printed wireframes for global shapes
Wireframe structures have been used to improve the printing
speed [26] and rapidly fabricate mesh models [23]. Using
wireframes, users can obtain a global concept of a work
as observed in many craft practices such as sculpting andlarge-scale architectures, and construct a new creation thatcan be called “3D coloring” (Figure 3b2 ). Wireframes haveopen surface and uncontrollable areas (on an edge or a facet).
Handling imperfections promotes users’ understanding ofmaterials, facilitating their learning from their progress andallowing them to become even more skillful [46].
Technique 3: Expressing textures
Texture is an important factor that is related to human tactile perception, as researched in various ways in the digital
fabrication domain [18, 38]. Although expressing fine textures with a 3D pen is fairly limited, a unique surface canbe created by the behaviors of the pen tip. This nuance iscomparable with smooth 3D printed textures. Figure 4 showsa variety of texture expressions: a bumpy 3D model using asurface processing function in modeling software, expressive
fused deposition modeling (FDM) with printing parameter
control [35], and the fuzzy skin option of Cura (Ultimaker3 ).
Technique 4: Integrating material properties
Recently, there has been great advances in various materials
2 These 3D models are made using Meshmixer
3 https://ultimaker.com/

such as flexible, conductive, water-soluble filaments, which
are available for 3D printing. These can be also fed into a 3D
pen to quickly and easily switch to introduce unique materiality, as demonstrated in making interactive objects [33].
Figure 5 shows examples of doodling with a conductive material and doodling on a scaffold printed with a water-soluble
material; the scaffold part can be removed after making.

Figure 5: 3D doodling with various materials: doodling conductive wires on the printed dented lines and creating wireframes with a printed soluble scaffold with Voronoi guides.

Technique 5: Doodling with printed on-demand tools
From the pilot study, we observed that participants employedvarious craft tools. As Mobile Fabrication [32] demonstrated,
a 3D printer can make on-demand tools that contribute tophysical making using a 3D pen. Printing an on-demand tool
is a collaboration between the pen and the printer. In the casewhere a user needs a tool, they can print one immediately
to help their own creation. Figure 6 shows a printed tweezer
and a manipulator added at the head of a printed scaffold.

Figure 6: 3D doodling with 3D printed on-demand tools.

Technique 6: Transforming planar figures to 3D shapes
With the thermoformable characteristic of materials, a printed
2D form can be folded into a 3D shape post-printing [2, 16].
Figure 7a shows the development of a box and a leaf deformed using a heat gun. The edges of the box and the veinsof the leaf are printed in PLA, while the other surfaces are
doodled in ABS. As ABS softens at higher degrees than PLA,
heat allows the user to selectively deform the parts printed
in PLA. The leaf object particularly benefits from users’ finetuning by hand, as such natural curves are otherwise difficult
to express solely by 3D printing.

3D Pen + 3D PrinterFigure 7: (a) 3D object post-deformed by heat and (b) functional objects created by combining 3D printed functional
primitives attached to a 3D doodled addendum.

Technique 7: Making with functional primitives
As demonstrated by 3D printed movable primitives [21], theaccuracy of a 3D printer helps create various functional objects such as a screw, hinge, spring, and matching bolt-nut
pair. Although the mechanism of these parts is simple, it isdifficult to design such functionality with a 3D pen. Figure 7bshows the combination of a printed hinge with 3D doodling.
5

WORKFLOWS: PRINTING IN DOODLINGWe detail a 3D printer setting and support system, aiming to
improve traditional 3D modeling to aid 3D doodling. In thepilot study, the craft scaffolds used by the participants werepreprinted. We implemented a system to use a 3D printer during 3D doodling and to support 3D printing tasks suggested
by our design techniques.
Implementation
As shown in [25], increasing the speed is important to tightly
engage users. With slicer settings, the system improves the
speed and enables users to print stencils and scaffolds for doodling. While 3D printing, a user can concentrate on hands-on
creation and then assemble printed parts or rework it to add
more details using the design techniques.
3D Printer and Slicer Setting. We used a 3D printer, which
is a traditional FDM (HICTOP Portable 3D printer), to implement our system. To increase the printing speed, the nozzle
diameter was changed from 0.4 mm to 0.8 mm, extruding athick stroke. This improves the printing speed with a higher
layer height. Figure 8 shows examples of printing with a
0.8-mm-diameter nozzle. This setup allows a Stanford bunny

Figure 8: Comparison of the printing time with a 0.8-mmdiameter nozzle.

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk

Figure 9: System for controlling a 3D printer. The systemallows users to print a 2D shape with three printing styles.

model to be printed in 19 min 55 s with a 0.4-mm layer heightand 25% infill density. By removing the infill structure andsetting the layer height to 0.6 mm, the bunny model can be
printed in 8 min 13 s. The printed results are low-fidelity;
however, these are sufficient for use with 3D doodling because users can obtain an abstract scaffold.
System. The system is implemented with C# as a plugin
for Repetier-Host4 and is loaded when this application starts(Figure 9). The system shows a canvas on which users candraw printing paths. A point is added by double-clicking
within the blank space or on an edge (the edge is then divided
into two edges). All points are draggable and can be deletedby double-clicking again. Each edge has two properties thatcan be set with check boxes: whether or not material is
extruded or not while moving along an edge and whether or
not the edge is a Bezier curve (two handles are shown).
The Printing paths drawn by users are converted into
Gcode in real time and previewed in a 3D view of RepetierHost. Information on the printing time and the amount ofmaterial for each style are always shown by the system. Notethat this Gcode includes additional commands for stable
printing. This Gcode is printable with three types of styles:
stencil (with thermal paper), contour, and fill (Figure 9, right).
Example Workflows
We present two example workflows here. We used PLA andthermal paper for facsimile, and the printing temperature of
the 3D printer and 3D pen was set to 190 ◦ C.
A tree branch with leaves. This example show various waysof making leaves by only tracing a printed stencil and byfilling a contour with a different color. A printed object canbe used as-is (Figure 10a–c). Three printing processes wereused with the same printing path, and the printing times
were 4 s (without preparation time for the paper), 24 s, and 2
min 48 s. A stem is drawn to combine the leaves, and these4 https://www.repetier.com/

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk

Figure 10: Example workflow using three different types ofprinting styles of the system.

are adhered using extruded material (Figure 10d). The whole
work takes approximately 20 min.
Rabbit. First, by printing a stencil and contour lines, asphere representing a body outline (Figure 11a) is created.
The printed contour lines contribute to obtain a relatively
accurate global shape, and the stencil is used for doodling
multiple wireframes, creating small grids to guide hand work.
Next, using the body outline, a body and head part are doodled (Figure 11b). By stroking the body with the extruding
material at tip of the 3D pen, fluffy animal hairs are expressed.
Finally, a tail, legs, and ears are added. Here, let us supposethat users want to create ears and legs that are sufficiently
large to support the whole body with a flat bottom (Figure11c). By using the system with the filling option, these parts
can be created by the 3D printer. Filling takes longer (inthis case, 5 min), but users can doodle a tail while printing
other parts. All parts are integrated into the body, and thewhole work takes approximately 30 min. Figure 11 shows theturn-taking between a human and the machine during thecreative process. As a user utilizes a 3D printer during theprocess and not as a final output appliance, they graduallydesign the product collaboratively with the machine.

Takahashi and Kim
21.6, SD = 1.3). All participants were randomly recruitedregardless of their prior experience with 3D printing and3D pen use. Most of them had no or little experience, anda few participants (P1, P4, and P8) had experience with 3Dmodeling and 3D printing. We informed the participants ofthe purpose and overview of the study, the expected length of
the study, the goal of the task (creating a 3D object designed
by him/herself), and that data will be collected. The study
was voluntary; participants could terminate or take a break
if necessary. We paid the participants approximately $100 tocompensate for their participation, regardless of the qualityof their work or actual working time.
Apparatus
We set up the user study in a laboratory at the university.
We provided two types of 3D pens to give more options
with size and grip: 7TECH 3D printing pen and CRITIRONIntelligent doodler pen. Unlike 3Doodler5 , these pens havefeed filaments with a diameter of 1.75 mm; this is the mostcommon thickness for commercial filaments. Thus, we canprovide a wide variety of materials as requested. The 3D
printer used during the study is a consumer-grade FDM with
a 0.8-mm-diameter nozzle for increasing the speed. We also
provided a laptop to use our system, example images, videos
of 3D doodling, and printed instructions. In addition to the3D pen and 3D printer, participants could also freely use
craft tools and materials, such as a tweezer, paper, a ruler,and clippers upon request. Participants’ work and utteranceswere recorded by using a camera placed in front of them.
ProcedureConsidering the contents and participants’ fatigue, we designed two-day sessions consisting of practice and planning(Day 1) and making (Day 2).

Figure 11: Example workflow using a 3D pen and 3D printertogether.

6

USER STUDY

In this section, we introduce a user study with eight participants. The objectives are to understand creative activities
with pen + printer; how a 3D pen, a 3D printer, and craft tools
are used in the process with the proposed techniques andworkflows; and how a 3D printer affects humans’ creativity.
We designed the user study referring to [4, 14, 39].
Participants
We recruited eight undergraduate/graduate students (P1–P8)
from the university (No. female students = 3, age mean =Practice (Day 1). After a demographic survey, a participant
learned how to use a 3D pen, tools, and a 3D printer in approximately 100 min. We provided printed instructions that
included contents, referring to the bootcamp section of the3Doodler book [1]. Participants might encounter challenges
during the study, as newcomers may not be familiar withthe given tools and setting, creating 3D objects using a pen
and printer together, and utilizing craft materials and tools
within a limited time. As indicated in [17], casual users often
lose their engagement owing to tedious troubleshooting andstruggling with non-creative tasks. Therefore, one of theauthors played a facilitator role and provided help when it
is related to techniques for handling tools.
Basic operation (15 min): We first showed how-to videos
and explained the usage of a 3D pen, its mechanism, the differences between PLA and ABS, and the cautionary measures
5 http://the3doodler.com/

3D Pen + 3D Printerfor using the devices (e.g., the temperature of the nozzle andthe odor of the molten material). Participants practiced threebasic doodling techniques: following 2D shape primitives
basic 3D doodling (pulling material), and filling a 2D plate
while texturing controlling the tips of threads.
2D stencils (20 min): The participants created simple 3D
shapes (a sphere, box, and cylinder) using stencils, a common
doodling practice.
Craft materials and design mat (15 min): We provided
craft materials such as crumpled paper, a glass bottle, a can,and a wooden stick; these can be used as a scaffold for 3D
doodling. The participants practiced using a design mat6 , aheatproof mat that helps users to draw fine lines.
3D printer and the system (15 min): We explained the3D printing process and our system and let the participant
try to use it. The participant then doodled using a printed
cylinder and box and printed contour lines using the system.
Planning (Day 1). After the practice session, participants
were instructed to plan on what to make for the next session.
The facilitator first let them provide any ideas but did notforce them to use a specific tool including a 3D printer andour system. The participants discussed the feasibility of theirplans with the facilitator, seeing examples of 3D doodled
art works (e.g., Figure 3), and searched for 3D models on
Thingiverse. If they were confused and wanted to know how
to use our system, we gave instructions to make use of thedesign techniques. The participants wrote down a work plan
for what to create on the next day of making (Day 2), thetools and material needed, and a reference image.
Making (Day 2). Participants started the making session
by reviewing the usage of a 3D pen and their work plan. We
allowed them to change their plan before and during themaking session. According to the plan, we prepared materials and tools. Since several participants required a 3D model,
the facilitator let them search on Thingiverse and use TinkerCAD7 for 3D modeling. While observing the process, wesometimes asked questions to promote think-aloud protocols.
They could terminate the session if they thought the work
was completed. After making, the participants answered aquestionnaire and freely talked with the facilitator about thework. The length of the making session depended on theparticipants (see the “Time” column in Table1).
Questionnaires
We created two questionnaires to evaluate the user study.
A demographic survey (S1) was used at the beginning. In
addition to the basic information, we asked participants to
self-evaluate their expertise in traditional arts and crafting,
6 https://www.the3dmate.com/
7 https://www.tinkercad.com/

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk
and their prior experiences in 3D printing, doodling, andmodeling. The wrap-up survey (S2) was to reflect on themaking session. S2 consisted of questions related general impressions, challenges, preferences, etc. using various factors.
We refer to the Creative support Index [11] and Shneiderman’s principles for creativity support tools [34]. Participants rated their experiences using a five-level Likert scaleand openly described them in written reflections.
Analysis
We collected quantitative and qualitative data including participant backgrounds (S1), the scores of collected from thesurvey (S2), and material and machine usage data. To observe the natural behaviors of participants, we conducted a
discourse analysis by transcribing recorded videos. To understand the characteristics of participants’ comments, we
coded them in two dimensions: topics (a 3D pen, a 3D printer,or craft tools) and the intent of a comment (opinion, requirements, or question). We also analyzed the relationship between participants’ work and the design techniques.
Results
Table 1 lists the selective feedback of S2, and Table 2 summarizes the analysis of the making session. All participants
were able to complete their work. The working time ranged
from approximately 30 min to 2 h depending on the participant. The 3D printer was used by almost all participants
except P8. P1, P2, and P4 used it with our system; P1 and P4
used Contour, and P2 used Fill. P3, P5, P6, and P7 used it toprint a 3D model. P8 only used the 3D pen and craft tools;
therefore, P8 did not answer the question on 3D printer use(A9 and A10 in Table 1).
The average scores were high in general for many of thefactors such as achievement, engagement, and enjoyment.
The participants liked to play with the 3D pen (A8) andtended to like their own work (A1). Very high scores include
5.0 ±0.0 for engagement (A3). Although the working time
was quite long, the participants answered that they did not
feel that it was long (A4). As for the reason for this score, P3
answered “because I can create intuitively,” and P6 answered“because it seems to have various elements of craft.” The scorefor exploration (A6) also implies these comments. On theother hand, no participant evaluated the perfection of theirwork as 100% (Q2 in Table 2). The score on whether theirwork is replicable by others was neutral (A5). The participants felt that the 3D printer improves the efficiency of theirwork (A9) and makes them more creative and successful(A10). They identified the part that they were in charge of(Q1 in Table 2). On the 3D printing, P1 answered “the 3D
printer can reproduce 3D data that I created with high fidelity,”and P7 answered “the 3D printer made it easy to fill things,
which is tough work by hand.”CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk

Takahashi and Kim

Findings
Difficulties with 3D Pen Use and Skill Development. The
most notable comments from the participants during thepractice session were regarding the difficulty of controllingthe 3D pen. The difficulties are categorized into four types:
stroke speed/direction, filling, bonding, and stringing. The
Stroke speed affects the shape of the extruded material. P1
struggled with doodling uniform lines, while P4 and P8 compared this characteristic to calligraphy. P1, P6, and P7 noticed
that the stroke direction affects the outcome because of theheat of the tip; especially, P6 compared this to a woody texture engraved with a chisel. P2 and P3 wrote that a doodled
part became bumpy and bloated. Filling was tedious work because the participants had to keep doodling under the same
conditions. P1 disliked this work and said “it is not humanwork...,” and P2 associated this with for a statement in a computer program. P8 said “I feel that I have become a 3D printer.”
Bonding is required to assemble a 3D shape from parts. P2
was confused by gathering material at a single place (e.g., at
the corner of a box). P5 compromised with this and said “anadhered part does not become clean anyway; it is no problem
Table 1: Selected statements with survey scores. Scores
are reported as average ± standard deviations. Since
P8 did not use a printer, A9 and A10 are from sevenparticipants.
1* 1: Strongly disagree – 5: Strongly agree
23
4
5

A1: I like the work that I created. (Achievement)
0
1
2
1
4
A2: I was able to express what I wanted to create.
(Expressiveness)
0
1
1
3
3
A3: I was very engaged in the activity. (Engagement)
0
0
0
0
8
A4: I feel the working time was long. (Flow)
5
2
1
0
0
A5: I think that it would be hard for others
to replicate my work. (Ownership)
0
2
4
2
0
A6: The 3D pen allows me
to embody my idea quickly. (Exploration)
0
1
2
1
4
A7: When planning, I was able toimagine how I would use the 3D pen (Expectation)
0
1
2
2
3
A8: I like the 3D pen. /I like to play with the 3D pen. (Enjoyment)
0
1
0
3
4
A9: The 3D printer improved the efficiencyof the activity. (Collaboration)
0
0
0
3
4
A10: I was more creative and successful when I usedboth pen and printer together. (Collaboration)
0
0
1
3
3

Scores
4.0 ± 1.2
4.0 ± 1.1
5.0 ± 0.0
1.5 ± 0.8
3.0 ± 0.8

4.0 ± 1.2

3.8 ± 1.0

4.3 ± 1.0

4.6 ± 0.5

4.3 ± 0.8

for me.” Stringing is a well-known problem in 3D printing,and it also occurs with a 3D pen. During the practice andmaking sessions, the participants often struggled to remove
a string from the extruded part and the tip of a 3D pen.
Although the participants faced various issues, they were
becoming used to controlling a 3D pen step-by-step. Facing
the above challenges contributes to learning how to use a 3D
pen. In the making session, the participants attempted a variety of techniques that they had experienced. P1 controlled
the tip of the 3D pen to express the texture of a seat of a chair.
P4 utilized textures presented with the design mat to create awaffle cone. By bonding wires, P6 created ice cream, and P7
created a strawberry. P8 created a dog using only a 3D pen
and developed a skill in his/her own way; P8 doodled a partin the unit of a facet and not a wireframe and mentioned “I
prefer assembling facets...it is similar to 3D modeling.”
Use of 3D Printing with 3D Doodling. To overcome challenges, participants used a 3D printer in their work. We
identified two times at which a 3D printer was used: at the
beginning or middle of work. The participants except P8
started the making session with 3D printing. Printed objects
tend to be large and simple shapes that may take a long time
to doodle with manual work. For example, P2 printed thelawn for the stadium and used it as a base for other parts. P7
printed a sponge cake that was a cylinder with a diameter of
60 mm, and it took 47 min to print. These uses are inspired
from technique 1; the 3D printer contributes to making it
easy for a user to reach a predefined goal.
P1 and P4 also used the 3D printer at the middle of making.
Using our system, P1 drew the frames of the chair, and P4
drew a ring and pillar for making the stand. Although theseparts are quite simple and take several tens of seconds, they
are important. P1’s frames supported the entire shape ofthe chair and needed to be of the same shape. P4’s ringsupported and fit the cone as a part of the stand because P4
was not able to create an ideal size of the ring with the design
mat. These are functional objects by combining 3D doodlingwith 3D printing (technique 7). As shown in the example
workflows, our system allowed the participants to print while
doodling. On the other hand, the “stencil” printing style ofthe system was not used. Instead of a stencil, P2 drew figures
on cardboard with a ruler and marker pen.
While 3D printing, the participants were tightly engaged
in 3D doodling. P6 doodled the foot of the bowl and answered“it was good to work with the 3D printer while making it print
a kind of large or fixed-size object.” P7 spared time to doodle
decorations (elaborate flowers and strawberries were P7’swork). Therefore, the tendency of their strategy was to leavea large or global concept to a 3D printer to reduce the loadof non-creative work.

3D Pen + 3D Printer

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk

Table 2: Results of the user study. “Material” indicates the amount of material used by each participant (bordered
areas mean for 3D printing). “Printer” indicates the things printed in the study and the printing time (boldfacemeans printing with the system). “Q1–Q3” are the questions selected from S2.
No.
Skill

P1
3D modeling

P2

P3

P4
3D printing

P5

P6
Drawing

P7
Drawing

P8
3D modelingchairstadium

bamboo shootice creamsun flower

parfaitcakedog

30 min65 min90 min2 hours

90 min95 min2 hours

2 hours

frames (0:18)*3 timeslawn (9:09)

lower part
(6:46)

berry (3:18)
ring (0:23)
pillar(0:27)

seed (8:43)

bowl (14:35)

sponge cake
(47:13)

–

Work

Time
Material

Printer

Q1
80%
80%
60%
75%
90%
80%
60%
100%
Q2
70%
60%
50%
90%
70%
85%
90%
80%
Q3
clipper
design matbottledesign mat
spatula, ruler
tweezers
clipper
tweezers
Q1: Indicate the proportion of the part that you did.
Q2: What is the degree of perfection degree of your work?
Q3: Except for the 3D pen and 3D printer, which tool did you use the most?

After printing, several participants customized a printed
object using a 3D pen and various materials (the materials
used are shown in Table 2). P2 doodled white lines on thelawn, P5 added bumpy textures to a cylinder to express thecenter of a sunflower, and P6 doodled patterns around an ice
cream bowl as decorations. Obviously, the various types andproperties of the materials used in this study (technique 4),
especially color, are used in their work for aesthetics. Texture
expressions using a 3D pen are inspired by technique 3.
Deciding What to Create Hands-on Versus What to 3D Print.
We found that some participants’ work could be improved
if they used the 3D printer. P2 marked the degree of perfection of his work as 60% because the ground and whitelines became unsatisfactory with his hand doodling. As it isdifficult to draw a straight line with a 3D pen, those parts
should have been printed. P3 noted that “because the top of
the bamboo shoot that was made was with short...I feel that
I have failed.” However, it took only 6 min to print, and P3
could have scaled up and printed a part again. P5 spent mostof the time doodling approximately 30 petals. P5 further said
“I wanted to bend a petal at the center,” but it is very difficult
to glue all petals. P8 did not use the 3D printer at all, but hemuttered the need to use 3D printing when filling the surface
after making the outline. In contrast to using technique 2,
P8 tried to obtain a global concept by him/herself.
Use of Craft Tools. Various craft tools were used by theparticipants (Q3 in Table 2). These were mainly for technicalskills such as picking up a part and removing unwanted

threads and oozed materials. Akin to the natural practices incrafting, the tools were used to trim, adjust, and rework theirobjects. While making, P1 always held a clipper and tweezers
to trim the object. P7 picked up a part using tweezers toprevent it from touching the pen tip; furthermore, P7 used thetweezers as a scaffold to support the structure of a strawberry.
P3 used a glass bottle to reshape the doodled skin of thebamboo shoot. P3 noticed that PLA can adhere to the surface
of a glass bottle, and the bottle generates a glossy surface. P2
used the design mat to create poles that have the same size
and a flag-like shape. P4 realized that the mat can express
a waffle texture and therefore doodled a large sheet to later
deform it into a cone. We found that the creative use ofcraft tools also empowers the participants’ creativity. If a 3D
printer contributes to the creation of on-demand tools, theactivity can be further improved, as shown in technique 5.
Several participants used the 3D printer as one of the craft
tools. To create the frame of a chair, P1 printed the same part
three times, mentioning “the third is a spare, just in case.” P4
used the printing bed as a heater to roll up a waffle cone.
Since the participant had experience with 3D printing, P4
understood the nature of the material and machine; PLA
can become soft by touching the heated bed. P6 explored a
support structure generated inside a bowl printed upsidedown. P6 first tried to get rid of the support using a clipper.
Later, P6 noticed that the support can be used as a pedestal
to settle the ice cream and thus did not try to completely
remove it.

CHI 2019, May 4–9, 2019, Glasgow, Scotland Uk
7

DISCUSSION

Efficiency Versus Creativity
In our study, participants faced four types of challenges.
Tedious iterations of simple and boring tasks, e.g., filling alarge surface, assembling and welding parts, and flattening
a surface, particularly made participants lose interest andthink that the process is inefficient. Participants were able toimprove efficiency by delegating such tasks to the 3D printer,focusing more on creative tasks.
On the other hand, fear of failure seemed to increase while
using a 3D printer and can hinder the exploration of creative
tasks. As a 3D printer can finish parts with accurate shapes,
users tried to take advantage of this benefit. We found thatusers tended to regard a 3D printed part as one of the completed parts and seemed to be resistant to doodling on it.
However, P4’s waffle cone that was post-deformed and P6’s
support structure printed in the bowl are serendipitous inventions during craft process. This implies that using a 3D
printer as a tool and manipulating partial outcomes are important factors that induce user’s creativity.
As summarized in Table 1 (A5), the answer regarding thereplicability of their work was neutral. This is a trade-off between the efficiency of the process and the expressed creativity. Thanks to 3D printing, 3D modeling, and online communities where users share free designs, everyone can replicate
objects by only downloading and modifying them. However,
the more a participant pursues fidelity and efficiency, theless the ownership of his/her work is, as they do not believethat the work is creative and feel ownership of the product.
Wrapping up the study, one participant who was good at 3Dmodeling stated that he can also create the same 3D datawith screen-based 3D modeling software.
Roles of Humans and Machines in Creative Making
A 3D pen enabled our participants to quickly validate andexplore their ideas, allowing direct manipulation of the tool
to externalize a conceptual idea. Aiming at inventing a newprocess in which humans can focus on creative tasks, theimportant roles of the 3D printer are to ensure that users
approach a goal step-by-step and to make users freely explore ideas. We observed that the participants printed large
parts (P2’s lawn, P5’s seed, and P7’s sponge cake) while doodling small details, and functional parts (P1’s frames and P4’s
stand) were well-produced with a 3D printer.
When 3D printing, the size, material, color, and shape ofthe object should be determined at the design stage and not
the physical fabrication stage. This informs us that 3D printing by a machine affects what is doodled by hand and how
large this doodle is. In our study, most participants started
the session with 3D printing; especially P2, P5, P6, and P7
were thinking about the relationship between the sizes of

Takahashi and Kim
the objects being printed and doodled. This process shouldbe mediated to promote exploration with a 3D pen, e.g., byprinting various alternatives. On the other hand, by experiencing this stage, users acquire an important key to creation;
users need to consider the size and arrangement of the final
outcome. This means that a 3D printer provides constraints
to exploration, and hopefully, users progress to the next stepwith this constraint. One of the steps is aesthetic customization using a 3D pen, which a user can easily improvise with
their fine hand skills. For example, it is difficult to makea multicolored object with conventional 3D printing alone(e.g., chocolate drizzle around ice cream) owing to the limited color palettes available. By obtaining a printed object,humans can use it as a canvas for personal expression.
A major difference between a 3D pen and a 3D printer isthat creation with a 3D pen does not require any concreteidea of creating the object before a user actually “starts” thecreation. Users can start by creating some primitives. It does
not involve batch processing to complete the final outcome.
While directly manipulating a 3D pen, users can learn various factors, e.g., the height of the nozzle creates a unique
texture [35], the stroke speed is related to the extrusion, andsome errors (e.g., stringing and layer shifting). It resembles
a traditional craft experience in that users gradually learn
how materials and tools behave while making and hence canadapt a strategy to deal with the techniques and 3D printer.
Limitations and Future Work
Our study aimed to observe creative tasks within a limited
time frame, in a limited space. The participants often considered the trade-off between the working time and what they
wished to make; they had to reduce the overall size of the object and disregard some details. It is viable that participants
can use the 3D printer in a limited manner to divide tasks forthe 3D printer to compensate for time limitation. Our next
goal is to not limit the time and space, so that participants can
explore greater varieties of constraints and possibilities. We
possibly may find a new significant role of the 3D printer as
an intelligent agent that can aid a human’s creative process.
8

CONCLUSIONSIn this work, we explored the opportunity and capability of
3D pen + 3D printer in creative making. On the basis of apilot study, we identified possible challenges and introduced
seven design techniques to innovate the 3D modeling processwith example workflows. We also conducted a user study toobserve the behaviors and roles of humans and machines
in creative activities. We found that the participants werehighly engaged in making and felt that these new workflows
helped them be creative. We discussed the roles of humans
and fabrication machines and the future of fabrication.

3D Pen + 3D Printer
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