Development of Tactile Graphics Production
Software for Three-Dimensional Projections
Mamoru Fujiyoshi1 , Takeshi Kaneko2, Akio Fujiyoshi3 ,Susumu Oouchi2 , Kenji Yamazawa4, Yuji Ikegami4 ,Yasunari Watanabe4 , and Yoshinori Teshima51

National Center for University Entrance Examinations
2-19-23 Komaba, Meguro, Tokyo, 153-8501 Japanfujiyosi@rd.dnc.ac.jp
2
National Institute of Special Needs Education
5-1-1 Nobi, Yokosuka, Kanagawa 239-8585 Japan
kaneko@nise.go.jp, oouchi@nise.go.jp
3
Department of Computer and Information Sciences, Ibaraki University
4-12-1 Nakanarusawa, Hitachi, Ibaraki, 316-8511 Japanfujiyosi@mx.ibaraki.ac.jp
4
Rapid Engineering Team, RIKEN Advanced Science Institute (ASI)
2-1 Hirosawa, Wako, Saitama 351-0198 Japankyama@riken.jp, yikegami@riken.jp, wistajp@yahoo.co.jp
5
National Institute of Advanced Industrial Science and Technology
1-2 Namiki, Tsukuba, Ibaraki 305-8564 Japan
yoshinori.teshima@aist.go.jp

Abstract. In this paper, we introduce tactile graphics production software for three-dimensional projections. A blind person can use this software without assistance from the sighted and produce tactile graphics ofthree-dimensional projections. With this software, we want to study thelimitation of tactile recognition of projections and improve the guidelinesof teaching projections.
Keywords: tactile graphics, the blind, three-dimensional projections,
universal design.

1

Introduction

Tactile graphics production software for three-dimensional projections is developed for the blind. A blind person can use this software without assistance fromthe sighted and produce tactile graphics of three-dimensional projections. The
software supports various types of projections such as orthographic projection,
oblique projection, and perspective projection. Once required parameters are inputted to the software, tactile graphics of three-dimensional projections will be
printed by a braille plotter printer.
Although the concepts of topological space and Euclidean space are learnablethrough tactile sense (haptic perception) and auditory sense, it is considered
K. Miesenberger et al. (Eds.): ICCHP 2010, Part II, LNCS 6180, pp. 541–547, 2010.
c Springer-Verlag Berlin Heidelberg 2010
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that it is almost impossible for the congenitally blind and the early blind toacquire the concept of projections because of a lack of experience in seeing lightand shadow [2,3,4]. However, there might be possibility that the concept ofprojections becomes learnable for them when a person starts abstract thinking
around age 11 or 12 years.
This study presents tactile graphics production software for three-dimensional
projections that is usable by a blind person. A blind person can obtain tactile graphics of various types of projections from any preferable viewpoint. The
software enables the blind to study the concept of projections by themselves.
Obviously, the tactile recognition of projections is much harder than the visual
recognition of projections. We want to study the limitation of tactile recognitionof projections and improve the guidelines of teaching projections.

2

Development of Bplot 3D

Tactile graphics production software for three-dimensional projections Bplot 3D
is developed.
2.1

Outline of Bplot 3D

Since we want to make Bplot 3D to be usable by a blind person without assistancefrom the sighted, it is developed as a preprocessor of the universal design tactile
graphics production system Bplot2 [1].
A user gives Bplot 3D a series of commands to produces tactile graphics ofa three-dimensional projection by specifying a type of projection, a viewpoint,
and a projection plane. Commands are written in a text ﬁle using our newly
designed control language for Bplot 3D. Because a command ﬁle for Bplot 3D
is a text ﬁle, it is editable with any text editors by any person who has learned
the control language. Therefore, Bplot 3D can be used by both the sighted andthe blind.
The software supports various types of projections. In general, projections
are classiﬁed into two categories, namely, ‘parallel projection’ and ‘perspective
projection’. Movrover, ‘parallel projection’ are divided into ‘orthographic projection’ and ‘oblique projection’. In parallel projection, the projection rays fromthe object to the projection plane are parallel to each other. Orthographic projection is a type of parallel projection where the view direction is orthogonal tothe projection plane. On the other hand, oblique projection is a type of parallel
projection where the view direction is not orthogonal to the projection plane.
In perspective projection, the projection rays are not parallel to each other but
they are emerging from the viewpoint.
2.2

Commands for Bplot 3D

To distinguish three-dimensional commands from ordinal commands of Bplot2,
every three-dimensional command starts from ‘3’.

Development of Tactile Graphics Production Software

543(1) Projection Type: A type of projections needs to be speciﬁed prior tothe other commands. For orthographic projection, the command is ‘3orgothographic’. For oblique projection, the command is ‘3oblique depth theta’. The
parameters ‘depth’ and ‘theta’ specify the fraction of depth versus width, andthe angle from the horizontal direction to the depth direction. For perspective
projection, the command is ‘3perspective’.
(2) Viewpoint: A viewpoint is speciﬁed with the command ‘3viewpoint x0
y0 z0’. Instead of the coordinates, a viewpoint can be speciﬁed as a directional
vector by the command ‘3direction theta phi’ for parallel projection.
(3) Wireframe: The wireframe of a ﬁgure is speciﬁed with the following commands. To deﬁne a plot, we use the command ‘3plot x0 y0 z0’. The command‘3plot’ has three parameters for the coordinates of point ‘x0 y0 z0’. To deﬁne aline segment, we use the command ‘3line x0 y0 z0 x1 y1 z1 DotPitch’. The command ‘3line’ has seven parameters for the coordinates of start point ‘x0 y0 z0’,
the coordinates of end point ‘x1 y1 z1’, and the dot pitch. To deﬁne connectedline segments, we use the command ‘3bline’. The command ‘3bline’ speciﬁes thedot pitch, the coordinates of start point, middle points, and end point, as follows:3bline DotPitch@x1 y1 z1@x2 y2 y2@x3 y3 z3
@...
@...
@...
@xn yn zn@9999 0 0

On the last line, ‘9999 0 0’ means the end of command. We can also deﬁne acurve line with the command ‘3spline’.
(4) Macros: We can deﬁne macros for three-dimensional commands by using
the command ‘3deﬁne identiﬁer replacement string list’. The comand‘3deﬁne’ replaces ‘identiﬁer’ into ‘replacement string list’ prior to the other threedimensional commands. For the readability of three-dimensional commands, we
can write parameters by identiﬁers instead of numerics.
2.3

An Example of Produced Three-Dimensional Projections

The following is an example of a command ﬁle to produce a oblique projectionin Fig. 1. The command ﬁle ‘File 3D’ describe a wire frame of cube that has thecenter as the origin and sides of the length 6. The type of projection and theviewpoint are also described in the ﬁle. When ‘File 3D’ is inputted to Bplot 3D,
the command ﬁle for Bplot2 ‘File 2D’ is obtained. From ‘File 2D’, Bplot2 canproduce tactile graphics with a braille plotter printer.
On line 5 and 6 in ‘File 3D’, a type of projections and a viewpoint are speciﬁed.
These lines are commented out in ‘File 2D’. On lines 8-10 and 50-51 in ‘File 3D’,

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File 3D

File 2D

1: /* Wire Frame of Cube
2:
by Oblique Projection
3: */4:
5: 3oblique 0.67 45
6: 3viewpoint 0 -10 0
7:
8: 3define dotpitch1 2.2
9: 3define dotpitch0 4.0
10: 3define end_of_data 9999 0 0
11:
12: define small 0
13: define middle 1
14: define large 2
15:
16: /// visible lines
17:
18: dot middle
19: 3bline dotpitch1
20:-3.0 -3.0 3.0
21:
3.0 -3.0 3.0
22:
3.0 3.0 3.0
23:-3.0 3.0 3.0
24:-3.0 -3.0 3.025:
end_of_data
26:
27: 3bline dotpitch1
28:-3.0 -3.0 3.0
29:-3.0 -3.0 -3.030:
3.0 -3.0 -3.0
31:
3.0 -3.0 3.032:
end_of_data
33:
34: 3bline dotpitch1
35:
3.0 -3.0 -3.0
36:
3.0 3.0 -3.037:
3.0 3.0 3.038:
end_of_data
39:
40: /// hidden lines
41:
42: dot small
43:
44: 3bline dotpitch045:-3.0 -3.0 -3.0
46:
-3.0 3.0 -3.047:
3.0 3.0 -3.0
48:
end_of_data49:
50: 3define point0 -3.0 3.0 -3.0
51: 3define point1 -3.0 3.0 3.0
52: 3line point0 point1 dotpitch053:
54: ///
55:
56: ff // formfeed

1: /* Wire Frame of Cube
2:
by Oblique Projection
3: */4:
5: //3D oblique projection (0.67, 0.25Pi)
6: //3D viewpoint (0.00, -10.00, 0.00)
7:
8: //3D defined dotpitch1 2.2 in rec. 1
9: //3D defined dotpitch0 4.0 in rec. 2
10: //3D defined end_of_data 9999 0 0 in rec. 3
11:
12: define small 0
13: define middle 1
14: define large 2
15:
16: /// visible lines
17:
18: dot middle
19: bline 2.200 //3D 5 points
20:-4.421 1.579 //3D point 1
21:
1.579 1.579 //3D point 2
22:
4.421 4.421 //3D point 3
23:-1.579 4.421 //3D point 424:-4.421 1.579 //3D point 525:9999 0 //3D end_of_data
26:
27: bline 2.200 //3D 4 points
28:-4.421 1.579 //3D point 1
29:-4.421 -4.421 //3D point 230:
1.579 -4.421 //3D point 331:
1.579 1.579 //3D point 4
32:9999 0 //3D end_of_data
33:
34: bline 2.200 //3D 3 points
35:
1.579 -4.421 //3D point 1
36:
4.421 -1.579 //3D point 237:
4.421 4.421 //3D point 3
38:9999 0 //3D end_of_data
39:
40: /// hidden lines
41:
42: dot small
43:
44: bline 4.000 //3D 3 points
45:-4.421 -4.421 //3D point 1
46:-1.579 -1.579 //3D point 247:
4.421 -1.579 //3D point 3
48:9999 0 //3D end_of_data49:
50: //3D defined point0 -3.0 3.0 -3.0 in rec. 4
51: //3D defined point1 -3.0 3.0 3.0 in rec. 5
52: line -1.579 -1.579 -1.579 4.421 4.000 //3D
53:
54: ///
55:
56: ff // formfeed

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545

Fig. 1. Oblique projection of a cube

macros are deﬁned. Parameters of other commands are speciﬁed by identiﬁers
instead of numerics. These lines are commented out in ‘File 2D’. On lines 12-14
in ‘File 3D’, there is the command ‘deﬁne’. Since this command is not a threedimensional command, Bplot 3D does not touch it. On line 18 and 42 in ‘File
3D’ and ‘File 2D’, the size of dots of dotted lines is speciﬁed with the command‘dot’. On lines 16-38 in ‘File 3D’ and ‘File 2D’, the wire frame of a cube on thevisible side is deﬁned. On lines 40-52 in ‘File 3D’ and ‘File 2D’, the wire frameon the hidden side is deﬁned. On line 56 in ‘File 3D’ and ‘File 2D’, the command‘ﬀ’ means the end of page.

3

Experimental Evaluation

In order to evaluate the usefulness of Bplot 3D, an experiment was conducted to
study which type of projection is suitable for blind students to recognize shapesof three-dimensional objects.
As experimental materials, we prepared tactile graphics of projections of fourkinds of geometric solids (cube, cuboid, cylinder, and tetrahedron) by the following drawing methods: (1) development view, (2) front view of orthographic
projection, (3) oblique projection without hidden lines, (4) oblique projection
with hidden lines, and (5) perspective projection with hidden lines. An example
of ﬁve tactile graphics of a cube is shown in Fig. 2.
Each ﬁgure was embossed on a sheet of braille-printer paper. The visible linesof wire frames were drawn by thick dotted lines (dot size 1.5mm in diameter anddot pitch 2.2mm) and hidden lines were delineated by thin lines (dot size 0.8mm
in diameter and dot pitch 4.0mm).
Subjects were eight totally blind students in a high school for the blind. Theirage ranged from 16 to 17 years old. They were classiﬁed into two subject groups:

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(1)

(2)

(3)

(4)

(5)
Fig. 2. Tactile graphics of a cube by the ﬁve drawing methods

the early blind and the late blind. In the early blind group, they suﬀered visual
impairments before 5 years old. In the late blind group, they suﬀered visual
impairments from 6 to 11 years old.
The subjects were asked to succeedingly observe tactile graphics of one of thefour geometric solids by one of the ﬁve drawing methods. Simultaneously, they

Development of Tactile Graphics Production Software

547

were required to rank the ﬁve drawing methods. The task was repeated for thefour geometric solids, respectively.
As a result of the experiment, we found that blind students prefer development
view as the best drawing method. Oblique projections with and without hiddenlines are at the second and third, and front view of orthographic projection andperspective projection are at the fourth and ﬁfth. From the result of analysis ofvariance and Scheﬀe’s comparison, the ranks of the ﬁve drawing methods weresigniﬁcant for all four geometric solids.
We also found that subjects in the late blind group recognized the concept ofprojection better than subjects in the early blind group through discussion withthem. However, we could not ﬁnd signiﬁcant diﬀerences between two subject
groups because the number of subjects was too small.

4

Conclusion

Tactile graphics production software for three-dimensional projections Bplot 3D
was developed for the blind. Bplot 3D was implemented as a preprocessor of theuniversal design tactile graphics production system Bplot2 [1]. Both the blindand the sighted can produce tactile graphics of projections easily.
As a result of the experiment, we noticed that it is not easy for the blind torecognize projections. However, the study of projection is necessary in naturalsciences for higher education [2,3,4,5].
To know the limitation of tactile recognition of projections and to improve
the guidelines of teaching projections, we need further studies.

Acknowledgement
This work was partially supported by Grant-in-Aid for Scientiﬁc Research (A)(18200049) of Japan Society for the Promotion of Science(JSPS).

References
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LNCS, vol. 5105, pp. 938–945. Springer, Heidelberg (2008)
2. Heller, M.A., Brackett, D.D., Scroggs, E., Steﬀen, H., Heatherly, K., Salik, S.: Tangible pictures: Viewpoint eﬀects and linear perspective in visually impaired people.
Perception 31, 747–769 (2002)
3. Kennedy, J.M., Gabias, P., Nicholls, A.: Tctile Pictures. In: Heller, M.A., Schiﬀ, W.
(eds.) The Psychology of Touch, pp. 263–299. Lawrence Erlbaum, Hillsdale (1991)
4. Kennedy, J.M.: Drawings from Gaia, a blind girl. Perception 32, 321–340 (2003)
5. Kennedy, J.M., Juricevic, I.: Haptics and projection: Drawings by Tracy, a blind
adult. Perception 32, 1059–1071 (2003)