vrml for kinematic and physical modeling and simulations

8/14/2019 VRML for Kinematic and Physical Modeling and Simulations

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VRML for Kinematic andPhysical Modeling andSimulations

Benjamin Pugliese

Mahesh Saptharishi


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Modeling Requirements

3-D representation with object interactionconstraints

Temporal consistency Real-time simulation and visualization of

the model Combining geometric and non-geometric

parameters for simulation (multi-modal)


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VRML Capabilities

Powerful representations for 3-D objects Temporal event generation User-defined object interaction primitives Interactive interface

Platform independent Easily extendible


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Applications

High-DOF kinematics modeling ( Robot Arm ) This demonstration exemplifies VRMLs capability

to simulate highly articulated structures. In this particular example, the combinations of rigid bodiesmove independently while being connected.Without a visualization tool such as VRML it would

be very difficult to imagine the motion of such amachine.
http://www.vuse.vanderbilt.edu/~fredrick/VRML/C3R3new.wrl


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Applications Cont.,

Collision and interference detection ( Kitchen ) Discrete event simulation involves proper execution of

scheduled temporal events and dynamic events. An

example of a dynamic event is collision detection andsubsequent action. This movie clip demonstrates asimple collision detection scheme implemented usingVRML. The action induced by the event is the change

in color of the colliding object. The user could define awhole host of events that could result from this catalystevent. The kinematics and the analysis for the eventdetection was done using JAVA. All visualization andsimulation of the rigid bodies was done with VRML.
http://www.cs.unc.edu/~geom/Collision_mpeg/kitchen.mpg


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Applications Cont.,

Interaction modeling for avatars ( Avatars ) Another application of VRML is tele-presence and

virtual reality worlds. This has been most commonlyused for chat rooms. An application that is slowlystarting to come up is virtual worlds. Virtual worldscan house shopping complexes, 3D-Web pages, etc..


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Application Cont.,

Space physics modeling ( NASA ) NASA has used VRML to model planetary motion,

space shuttle design, and simulation of missions.The demonstrations in the hyperlink show theability of VRML to simulate environmental eventssuch as temperature, surface winds, light etc. NASAis primarily interested in VRML because of itsability to very quickly develop proof-of-concepts.
http://nssdc.gsfc.nasa.gov/misc/talks/vrml/slide_1.html


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Applications Cont.,

Rapid prototyping ( Sojourner ) NASA used VRML in parts of the MARS mission

planning stage. This demonstration is the NationalGeographic Societys rendition of how the missionwas executed. Design of Sojourner and Pathfinder and the simulation of its components can also beseen. Note the power of VRML as an effectivevisualization tool. This particular demonstration alsoshows the power of multimedia content to design,develop and demonstrate new ideas.
http://www.nationalgeographic.com/mars/


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Disadvantages

Interpreted nature of VRML makes it slowfor display of complicated simulations

Object representations and interaction primitives can take up a lot of memory

Using VRML for simulation involves afairly steep learning curve

No standard interface for extensions


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Conclusions

VRML provides a very elegant tool for simulating and visualizing complexinteractions

Its popularity is constantly increasing inthe modeling domain

It has the appeal for distributed, internet based design and modeling


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References and Resources

Web 3D Consortium The VRML Repository The Annotated VRML Reference Manual I-COLLIDE

Collision detection with VRML VRML and the Visualization of Space Scie
http://www.vrml.org/http://www.vrml.org/http://www.cs.unc.edu/~geom/I_COLLIDE.htmlhttp://www.wasabisoft.com/Book/Book.htmlhttp://nssdc.gsfc.nasa.gov/misc/talks/vrml/http://nssdc.gsfc.nasa.gov/misc/talks/vrml/http://www.wasabisoft.com/Book/Book.htmlhttp://www.cs.unc.edu/~geom/I_COLLIDE.htmlhttp://www.vrml.org/http://www.vrml.org/


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Answers to questions Steep learning curve for VRML simulation?

why? better method? Using VRML, to create simple 3D worlds is very

easy and effective. The complications arise whentrying to program 3D worlds with events todesignate interactions and dynamics in the world.The event structure, though powerful, iscomplicated at first glance. It takes some time tounderstand how to use the event architecture incombination with the VRML reality engine. Other methods such as CAD have similar problems, butthe capabilities of each differ. VRML is more of a

general purpose simulator while CAD is moreapplication specific.


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Answers to questions How to include kinematics formula into

VRML? VRML provides for JAVA and C/C++ interfaces for

backend computations. This is necessary becauseVRML is largely interpreted and large nativecomputations slow it down. The I-COLLIDE

package (linked as a reference) is an excellentexample of using JAVA as the computational

backend for VRML-based simulation. Please alsosee http://www.igd.fhg.de/CP/scriptgen/ . This web

page provides a java script template generator toinsert within VRML for computations. The VRML

Repository has many other JAVA resources.
http://www.cs.unc.edu/~geom/I_COLLIDE.htmlhttp://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.igd.fhg.de/CP/scriptgen/http://www.cs.unc.edu/~geom/I_COLLIDE.html

vrml for kinematic and physical modeling and simulations

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