Virtual Scissors in a Thin Haptic and Force Feedback Environment

Paper: jc13-3-3798:2009/4/3

Virtual Scissors in a Thin Haptic and Force Feedback
Environment
Kenji Funahashi∗ , Daisuke Kubotani∗2 , Yuji Iwahori∗3 , and Koji Tanida∗4∗ Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Japan

E-mail: kenji@nitech.ac.jp∗2 Rinnai Corporation, 2-26 Fukuzumi-cho, Nakagawa-ku, Nagoya, Japan∗3 Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, Japan∗4 Honda R&D Co., Ltd., 4630 Shimotakanezawa, Haga-machi, Tochigi, Japan[Received 00/00/00; accepted 00/00/00]

The virtual scissors using virtual hands we propose enable users can cut virtual paper with their own hands.
One purpose of our proposal is to facilitate implementing different tools simply by changing softwareparameters. Another is to make a general-purpose
system with small-scale input and output devices forgeneral applications, e.g., only using thin haptic information and force feedback. With such virtual reality (VR) scissors, we introduced feedback to cover
any impressions such as interface interference duringuse. We evaluated whether an interaction occurred between vibration feedback and sound effects. Using thissystem, we found that users could manipulate virtual
scissors through a data-glove similar to the use of real
ones.

Fig. 1. Scissors and paper model.

We begin with an overview of virtual scissors and informative control, proceed with experiments and results, andclose with conclusions. This technique might be not only
for virtual scissors system but also for any virtual reality
system to use at personal home [5].

2. Virtual Scissors
Keywords: virtual scissors, haptic and force feedback,thin feedback

1. Introduction
Many experiments in virtual reality (VR) research andobject manipulation involve glove-like input devices [1].
The latest developments include gloves with vibrators in
the fingertips for conveying information or that provide
feedback forces to individual fingers.
Introducing haptic and force feedback usually involves
larger, more expensive equipment, although fields suchas medicine prioritize precision over cost, e.g., in the development of virtual scissors in which force feedback is
considered [2].
In this research, we considered the virtual scissors system with thin haptic and force feedback [3, 4]. The
system consists of only vibration feedback elements forsmall-scale size and low-price, because our goal is widely
generalization. Among the proposals we considered arecontact-point and noncontact-point vibration, introducing
a cutting sound which is not calculated but a like soundeffect, and providing an intentional feedback delay givinga “paper-cutting” sensation to the user, e.g., cutting thick
paper.
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2.1. Scissors and Paper Model
We consider right-hand movement moving, opening,and closing a pair of scissors, but not picking up or putting
them down (Fig. 1). Scissors are in continuous contact
with the first thumb and forefinger joints, so we consider
blade contact as a working point.
Virtual paper is defined as a flat plane with collective
vertices connected by lines called a boundary. Lines created by cutting are called cut-lines. The only user operations considered are opening scissor blades, moving themwhile open, and closing them. Slide cutting as using knife
is not allowed, then the finite-size line of the collective
contact points is defined as cut-line after the operation of
blade closing. Hence separating paper is not consideredin this experiment.

2.2. Interaction Model
Scissor blades can interfere in the paper at the contact
point, although the handles cannot. Virtual hand interference with paper is not considered. Then the path of thecontact point is generated. The path is calculated as the
cut-line only when it is inside boundary, although a pathis not generated if the scissors is closed with no contacts
on the paper.

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Funahashi, K., Kubotani, D., Iwahori, Y., and Tanida, K.

Sound Data

begin

end

Fig. 3. Playback of cutting sound.

Fig. 2. Vibrators on glove.

3. Feedback
3.1. Vibration
We give the operator some cutting feelings using vibrators of data glove, although it is different from the strict
force feedback. On the glove, vibrators are set on the second and third joint of each fingers and palm (Fig. 2). First
we have to consider the strength and the position of vibrational stimuli. Three levels of the strength were wethought as below; 1) an operator do not feel it excessively,2) can feel it, and 3) feel strongly.
In considering where vibration would operate best, weat the first thought it is the finger which contacts with scissors. Cutting feeling by artificial vibration is already different from actual one, and vibrators are unfortunately set
on the back of the finger. We used our ingenuities to vibrate other fingers which have no contacts with scissors
and also palm in order to get quasi-feeling. Considering
simplification, the system was set to give a constant vibration in action of cutting.
3.2. Cutting Sound
When cutting virtual paper, the system gives an operator CG (Computer Graphics) image to observe the virtual world visually. Using this system (probably manyother systems), it gives not only CG image but also cutting
sound. The sound was not computational, but recorded of
the real sound of cutting. When cutting operation, it decided the playback part as follows (Fig. 3). The soundwhen the paper is cut was not considered for the thickness, the material of paper and also the shape, material
and attitude of scissors, but considered for the position ofcontact point of scissors’ blade. The playback part was
decided only by the contact point. The beginning point2of playback part is decided by the position of the contact
point for whole of the blade and the end point is decided
by the contact point when cutting operation ends in thesame way.
In considering what sound would be best, we tend toregard as the same sound when using the same thickness
paper of CG image, the same shape scissors and the same
size scissors of CG image. However the system is alreadydifferent at many points. For example, the visual image
in 2D Display is limited, the image is not so real, andhaptic and force feedback is thin. Then evaluation was
done with some recorded sounds; some kinds of scissors
and two materials as paper and cloth.

3.3. Intentional Delay
Heavy expression is sometimes introduced when execution speed of PC is slow. As we drag a mouse cursor oran icon, we feel it heavy when its response is a little delayed. We made an experiment as a new method to makean operator feel like cutting a thick piece of paper withscissors in the virtual space by an intentional feedback
delay.
In related research, computer-mouse movement on amonitor was made faster or slower than actual operation.
The system was impressed as a hillclimb and a downhill
respectively. It gave an operator pseudo haptic [6].
Most of operator usually think high execution speed isbest. However we cut thick paper slowly, and can not cut
it fast because of the thickness. Our experimental system can input the value of an operator’s hand motion andmovement, calculate the interaction to the virtual environment and display the CG at 20 images per second. In
other words, it contains 50 ms delay resignedly. But wecan feel that we manipulate by ourselves. We generally
can say that a virtual reality system is realized when the
delay is under 100 ms. So we tried to make the delay over
100 ms (Fig. 4).

4. Experiments and Results
4.1. System Overview
The virtual scissors system was implemented on a
PC (Pentium4, 2.80 GHz, 1 GB memory) in C language. Hand positioning was detected by a Polhemus
3SPACE FASTRAK and finger angles by Immersion Cy-

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Virtual Scissors in a Thin Haptic and Force Feedback Environment

Table 1. Vibration reality and level.

pattern1
2
3
4
5

point (average)
4.22
5.27
5.00
3.61
3.16

Fig. 4. Delay and pseudo haptic.

Fig. 5. System and overview.

Fig. 7. Scissors A-G.

Fig. 6. Execution screen.

3. : finger strength 2, palm strength 3
4. : finger strength 1, palm strength 2
5. : finger strength 3, palm strength 2
where strength is:

berTouch (Figs. 5 and 6). The CG image was refreshed at
20 frames/s. The virtual hand was assumed to be an adultmale’s. The 190 mm virtual scissors had 80 mm blades.

4.2. Vibration
In all experiments, the monitor was vertical and virtual
paper tilted at 45-degree angle to the monitor. The righthanded subjects numbered six and had 10 minutes to workwith the system before experiments. The subject could
draw forth the virtual paper by the left hand movement.
Vibration experiment evaluated the strength and the position of vibration. Note that cutting sound effects were
not used in this experiment. Pre-experimental study suggested that vibration at the ring finger and little finger gave
poor results, as did strong vibration, so we focused on the
thumb, forefinger, middle finger, and palm as vibration
points, and set five patterns:
1. : finger strength 2, palm strength 2
2. : finger strength 2, palm strength 1
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1. : Not felt excessively.
2. : Felt.
3. : Provieds no vibration.
Each subject tried each pattern three times, for a totallyof 15 times, in random order, evaluating the level as from
1 to 7 points after each test (Table 1). Results showedthat felt palm vibration was effective, folloew by the middle finger and forefinger, where it was observed that thesefingers sometimes contacted to the outside of handle ofscissors in the pre-experiment result.

4.3. Cutting SoundIn cutting sound experiments, we evaluated effective
cutting sound, and whether the real sound was necessary
also in virtual scissors which was modeled with the realshape and material.
We prepared printer paper sheets, pieces of cloth
0.3 mm thick, and seven pairs scissors (Fig. 7), 6 of stainless steel (A to F) and blades 45, 60, 75, 105, 140, andJournal of Advanced Computational Intelligenceand Intelligent Informatics

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Funahashi, K., Kubotani, D., Iwahori, Y., and Tanida, K.

Table 2. Reality in different environments.

environment
12
3
4

point (average)
2.33
3.83
5.33
6.00

Table 3. Evaluation of cutting sound.

sound
D
G
F
Fig. 8. Evaluation of cutting sound.

40 mm long. Scissors F, unlike A to E, which had plain
straight blades, had a zigzag edge (pinking shears). Scissors G had a 100 mm blade and were of steel (dressmaker’s shears) of the same size and shape as scissors D.
We recorded 14 types of cutting sound, and had six subjects evaluate them through a VR system, then the same
14 but original real sound. Note that no vibration feedbacks was provided in this experiment. Each subject listened three times to each sound in random order, evaluating it as good (+1 to +3) to bad (−1 to −3) (Fig. 8).
Scissors D and E scored higher than A to C. The cutting
sound start position differed from the end one, with thedifference increasing with blade length and longer blades
being viewd more favorably. Scissors G and D had thesame blade length but G scored lower in the VR environment, possibly because some subjects felt cutting operation was light as seen in their comments because steel
scissors made sound with high frequency. We think thatan effective sound frequency is necessary for the cutting
operations.

4.4. Vibration and Sound EffectSubjects were then asked to evaluate the effects of vibration feedback and cutting sound together under the following conditions:
1. : CG image alone
2. : CG image and vibration feedback
3. : CG image and sound effect
4. : CG image and vibration and sound.
The vibration pattern was set on the 3rd pattern and thecutting sound was set with the D sound mentioned before.
Six subjects evaluated these conditions with scores of 17 points (Table 2). The vibration heightened evaluation
certainly, although the effect by vibration feedback was
lower than sound effect.

4

vibration 1
5.33
5.16
4.00

no vibration
5.16
4.83
2.83

Table 4. Evaluation of vibration.

vibration
2
1
5

sound D
6.00
5.66
3.33

no sound
5.16
4.33
2.50

4.5. Interaction Between Vibration and SoundTo evaluate whether vibration and sound effect influenced each other, i.e., interacted. The cutting sounds theD (highest point), the G (middle point) and the F (lowest point) mentioned before are prepared for this experiment. The vibration pattern No.2 (highest point), No.1
(middle point) and No.5 (lowest point) mentioned in thesection 4.2 are also prepared.
Each subject was asked to execute the following tasks:
1. For the cutting sounds D, G and F, subjects manipulated the scissors system with vibration pattern 1,
and without any vibration, where they did not know
there were only three patterns of the cutting sound.
They answered the evaluation as level among 1 to 7
point for the sounds, not for the total system.
2. For the vibration pattern 2, 1 and 5, subjects manipulated the scissors system with cutting sound D, andwithout any sound effect, where they did not know
there were only three patterns of the vibration. They
answered the evaluation as level among 1 to 7 point
for the vibration, not for the total system.
The results of average point are shown in Tables 3 and4. The evaluation of both increased when adding anothereffect. It seemed there is an interaction between them andone effect could make another effect more effective.

4.6. Intentional Delay
Our system could be input motional values by the device calculate the interaction and display the CG image
and cutting sound at 20 times per a second. It contained
50 ms delay, but we can generally judge it as real-timesystem under 100 ms delay in virtual reality field.

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Virtual Scissors in a Thin Haptic and Force Feedback Environment

Table 5. Evaluation of delay.

subject
a
b
c
d
e
f
g
h

env. 1
good
good
good
good
good
good
normalnormalenv. 2
good
normalnormalnormalnormal
good
good
good

env. 3
bad
bad
bad
bad
bad
bad
bad
bad

The following three conditions were prepared:
1. : no delay (50 ms delay)
2. : 200 ms delay
3. : 500 ms delay.
And the system gave the subjects feedbacks of CG image,vibration and cutting sound in each environment.
10 minutes after experience at condition 1, eight subjects cut the virtual paper at each remaining condition.
They tried each condition in randomized order, and answered evaluations as good/normal/bad and comments forthem.
Two subjects evaluated condition 2 better than condition 1, and other two subjects answered the same evaluation for condition 1 and condition 2 (Table 5). We got
comments for every condition 2 experiments like;

Intentional delay is effective as force feedback. The
appropriate delay of minuteness makes an operator feel
heavy and/or hard. Nevertheless our experiment after theannouncement that the virtual paper was thick showed thedelay was effective very much. Only delay is not so effective and the delay is probably just supplementary. So,for example, we have to use this method assuming thick
paper of CG.
Their size and price preclude using many of the force
and haptic feedback devices developed thus far for homeuse, while the vibrator system is used for the silent modeof mobile phone and video game controller. Although thedata-glove we used is very expensive one, there are/weresome data-gloves for video game in the market. It would
be able to make a data-glove with vibrator at a low pricein the future. Using this data-glove and the method proposed, various virtual reality system might be produced
and sold, for example, for our home through the internet.
Despite some favorable results, bugs remain. We could
not test sufficient statistical hypotheses for experiments
because of too few subjects, meaning for example, that we
tested some vibration and strength patterns but cut soundand delay, leaving them for future work. The touchable
Internet shopping system also remains to be realized.
Acknowledgements
This research was supported in part by Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research (C)(20500168), a Chubu University Grant, and the Nitto Foundation.

• It was heavy.
• Subject felt cutting thick paper.

References:• Scissors/paper is hard.

Four subjects evaluated condition 1 better than condition
2 according to their comments. As for condition 3, we got
comments like;• It was stressful.
• It was difficult to cut it straightly.
• Subject felt being old person.

Then we announced to them that the virtual paper was
thick like cardboard in fact, and asked them to try again
and answer again. So all of evaluations of condition 2
turned good, and the six of them was better than condition 1. From these results, the minuteness delay of haptic
information is effective as force feedback. That is, time
can be perceived as force.

[1] K. Funahashi, T. Yasuda, S. Yokoi, and J. Toriwaki, “A Model for
Manipulation of Objects with Virtual Hand in 3-D Virtual Space,”
Systems and Computers in Japan, Vol.30, No.11, pp. 22-32, 1999.
[2] A. M. Okamura, R. J. Webster III, J. T. Nolin, K. W. Johnson, andH. Jafry, “The Haptic Scissors: Cutting in Virtual Environments,”
Proc. the 2003 IEEE Int. Conf. on Robotics & Automation, pp. 828833, 2003.
[3] K. Tanida, K. Funahashi, M. Ohmi, and M. Kusumi, “Embodiment
Evaluation for Tools of Virtual Reality Technology -A Trial Evaluation by Measuring Hemodynamic Change in the Brain-,” Transactions of Virtual Reality Society of Japan, Vol.12, No.1, pp. 3-10,
2007 (in Japanese).
[4] K. Funahashi, D. Kubotani, K. Tanida, and Y. Iwahori, “Pseudo
Haptic Expression by Presentation Delay in Virtual Scissors System,” Proc. the 12th Virtual Reality Society of Japan Annual Conf.,
pp. 393-394, 2007 (in Japanese).
[5] K. Funahashi, Y. Kuroda, and M. Mori, “A Study for Touchable
Online Shopping System with Haptical Force Feedback,” Proc.
ICAT2008, pp. 297-300, 2008.
[6] A. Lecuyer, J.-M. Burkhardt, and L. Etienne, “Feeling Bumps andHoles without a Haptic Interface: the Perception of Pseudo-Haptic
Textures,” Proc. ACM SIGCHI, pp. 239-246, 2004.

5. Conclusions
In experiments to evaluate virtual scissors, vibration
feedback is effective as force feedback, and the vibrational stimulus where man can realistically never touch,i.e., palm is also effective. Cutting sound feedback is effective on operational feeling, the sound which is replayedwith the real scissors is also effective even if virtual scissors differ in size from actual scissors. An interaction occurs between vibration feedback and sound effect.
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Funahashi, K., Kubotani, D., Iwahori, Y., and Tanida, K.

Name:

Name:

Kenji Funahashi

Yuji Iwahori

Affiliation:

Affiliation:

Information Technology Center, Nagoya Institute of Technology

Department of Computer Science, Chubu University

Address:

Address:

Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan

1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan

Brief Biographical History:

Brief Biographical History:

1998 Ph.D. in Information Engineering, Nagoya University
1998- Joined Nagoya Institute of Technology
2003 Visiting Researcher, University of British Columbia
2005- Associate Professor, Nagoya Institute of Technology

1988 Ph.D. in Engineering, Tokyo Institute of Technology, Japan
1988- Research Assosiate, Educational Center for Information Processing,
Nagoya Institute of Technology, Japan
1992- Assosiate Professor, Nagoya Nagoya Institute of Technology, Japan
2002- Professor, Nagoya Institute of Technology, Japan
2004- Professor, Dept. of Computer Science, Chubu University, Japan(Visiting Professor, Dept. of Comp. Sci., UBC, Canada)

Main Works:• “Virtual Liquid Manipulation Using General Shape Vessel,” Proc. IEEE
VR2001, pp. 283-284, Mar. 2001.
• “Swimming Across the Pacific: A VR Swimming Interface,” IEEE
Computer Graphics and Applications, Vol.25, No.1, pp. 24-31, Jan./Feb.
2005.

Membership in Academic Societies:• The Institute of Electrical and Electronics Engineers (IEEE)• The Virtual Reality Society of Japan (VRSJ)• The Institute of Electronics, Information and Communication Engineers(IEICE)• The Japanese Society for Medical and Biological Engineering (JSMBE)

Main Works:• “Self-Calibrated Neural Network Based Photometric Stereo,” Int. J.
Comp. & Info. Sci., Vol.3, No.1, pp. 31-40, Mar. 2002.
• “Obtaining Shape from Scanning Electron Microscope using Hopfield
Neural Network,” Journal of Intelligent Manufacturing, Vol.16, No.6,
pp. 715-725, Dec. 2005.

Membership in Academic Societies:• The Institute of Electrical and Electronics Engineers (IEEE)• The Institute of Electronics, Information and Communication Engineers(IEICE)• Information Processing Society of Japan (IPSJ)• Knowledge-Based and Intelligent Information & Engineering Systems
(KES)

Name:

Name:

Daisuke Kubotani

Koji Tanida

Affiliation:

Affiliation:

Rinnai Corporation

Assistant Chief Engineer, Honda R&D

Address:

Address:

2-26 Fukuzumi-cho, Nakagawa-ku, Nagoya, Japan4630 Shimotakanezawa, Haga-machi, Haga-gun, Tochigi 321-3393, Japan

Brief Biographical History:

Brief Biographical History:

2006 M.E in Information Engineering, Nagoya Institute of Technology
2006- Joined Rinnai Corporation

1992- Joined Honda Motor
1992- Joined Honda R&D
2005 Ph.D. from Kyushu University

Main Works:• “A Study for Virtual Scissors System under Thin Haptic and ForceFeedback Environment,” SCIS & ISIS 2008, pp. 1448-1453, Sep. 2008.

Main Works:• “A Hierarchical Model of Operational Anticipation Windows in Driving
an Automobile,” Cognitive Processing, Vol.7, No.4, pp. 275-287, Dec.
2006.

Membership in Academic Societies:• The Society of Automotive Engineers of Japan (JSAE)• Japan Ergonomics Society (JES)• The Japanese Association of Traffic Psychology (JATP)• Japanese Society for Physiological Psychology and Psychophysiology(JSPP)

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