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Using Visual Cues of Contact to Improve Interactive Manipulation of Virtual

Objects in Industrial Assembly/Maintenance

SimulationsJean Sreng, Anatole Lécuyer, Christine Mégard, Claude Andriot

jean.sreng@cea.fr

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Outline

•Introduction•Type of information to visualize•Related work •Visual cues of contact

– Contact glyphs– Contact lights

•Preliminary evaluation•Conclusion

OUTLINE

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Outline

•Introduction•Type of information to visualize•Related work •Visual cues of contact

– Contact glyphs– Contact lights

•Preliminary evaluation•Conclusion

OUTLINE

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Introduction

• Context: Virtual prototyping, assembly/maintenance simulations

• Problem: Complex industrial geometries– Multiple contact– Hard manipulation

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Two types of information to visualize

For all contacts :– Local minimal distances [Johnson et al., 03]

• First point• Second point

– Contacts• Contact point and orientation• Contact force

“ Imagine two models that have just collided. This collision can be represented at a single point on each surface [...]. If the models move apart, this pair of points tracks the local minimum distance and represents the potential future contacts between entire sections of these two models. “

[Johnson et al., 03]

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Related work

– Visual aids [McNeely et al., 06]

– Visual glyphs [Redon, 02]

– Visual cues [Wanger et al., 92]

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Visual cues

• We have chosen to develop two novel types of visual feedback :– Contact glyphs

• Proximity• Effort• Hybrid

– Contact lights

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Outline

•Introduction•Type of information to visualize•Related work •Visual cues of contact

– Contact glyphs– Contact lights

•Preliminary evaluation•Conclusion

OUTLINE

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Proximity – Contact - Forces

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Proximity glyphs

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Proximity glyphs

• Video

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Effort glyphs

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Effort glyphs

• Video

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Hybrid glyphs

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Hybrid glyphs

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Hybrid glyphs

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Hybrid glyphs

• Video

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Glyph filtering

•Reduce the number of displayed glyphs :– Filtering technique based on user’s motion

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Outline

•Introduction•Type of information to visualize•Related work •Visual cues of contact

– Contact glyphs– Contact lights

•Preliminary evaluation•Conclusion

OUTLINE

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Contact lights

•Lights are disposed at the contact point :– Do not overload the visual feedback– Can be combined with glyphs

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Without visual feedback

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Spherical lights

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Conical lights

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Contact lights

• Video

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Contact lights and hybrid glyphs

• Video

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Outline

•Introduction•Type of information to visualize•Related work •Visual cues of contact

– Contact glyphs– Contact lights

•Preliminary evaluation•Conclusion

OUTLINE

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Preliminary evaluation

•Collect data about users’ preferences•Participants were asked to perform an industrial

assembly operation– Without visual cues– With each visual cues

•They had to fill a subjective questionnaire

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Experimental setup

SpacePilot

PhysicalEngine

(GVM/LMD)

GraphicalEngine(VTK)

P4 2.4GHz / NVidia Quadro 4

30 FPS

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Experimental evaluation

•18 participants•Procedure :

– Learning phase (20 min)– Testing phase (20 min)

• All the visual glyphs were presented• They were asked to complete the assembly• They have to test successively all glyphs• They were no time limited• They could freely test again any glyph

– Fill subjective questionnaire (5 min)

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Collected data

•Rank 5 visual effects according to 4 preference criteria :– 5 visual effects :

• Apparition of a light• Apparition of a glyph• Color change• Size change• Deformation

– 4 criteria :• Understanding the blocking situations• Perception of distances• Perception of contact forces• Focus on contact area

•Preferences among the shapes : disk / sphere / arrow ?•Preferences about filtering : with or without ?

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Results

•χ2 test on ranks and parametric ANOVA test on rank used as value

•Participants were able to associate effects and visual cues

•Contact lights : Preferred to focus attention– Some found it useful for distances appreciation

[Kjelldahl et al.]

– Decrease the visual workload– Can suggest information in occlusion context

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Discussion

•Glyphs : Preferred for distances and contact forces– Are reported to help precise manipulation– Color gradient is easily understood (distances)– Size change are globally well appreciated

•Deformation : Preferred for contact forces– Can be naturally perceived (Meet up the

pseudo-haptic effect [Lécuyer et al., 00])

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Conclusion

•We proposed visual cues to improve manipulation in industrial assembly/maintenance context :

– Glyphs• Arrows, disks, sphere• Proximity, Effort, Hybrid

– Filtering– Lights

•Preliminary evaluation suggested that the visual cues and their associated visual effects seemed useful

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Further work

•Quantitative evaluation in complex industrial context – Compare visual feedback and haptic or audio

feedback•Develop contextual visual cues

– Adapt to different situations•Complementary technique could be investigated :

– Camera motions– Automatic and multiple viewpoints– Magnifying effects– Transparency on occlusions

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?Question

Thank you for listening

Questions ?