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VRML in Plasma Physics: two applications. Boyd Blackwell - Plasma Research Laboratory, RSPhysSE, ANU - partially supported by Princeton Plasma Physics Laboratory under DOE contract xxxxxxxxx. Aims. Conceptual 3D Magnets Plasma Confinement Simple, readily available interface (Web?)
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VRML in Plasma Physics: two applications Boyd Blackwell - Plasma Research Laboratory, RSPhysSE, ANU - partially supported by Princeton Plasma Physics Laboratory under DOE contract xxxxxxxxx
Aims • Conceptual 3D Magnets Plasma Confinement • Simple, readily available interface (Web?) • rapid design and evaluation cycle • Standard capable of describing complex objects • levels of detail • Future? • further use in detailed design (diagnostics) • reusable data description (getting tired of GL)
Design of Plasma Devices • Choice of Magnetic Configuration • most important! • requires 1000s of hours of supercomputer time only parts can be made interactive (Ex 2) • Realization of Configuration (Example 1) • 3D placement of sets conductors • look for • intuition about aspects of magnetic field shape • mechanical interference, support possibilities Design of the Wendelstein VII-X stellarator: Nuhrenberg et al. References:
Alternatives • GL OpenGL • initial work on H-1 • why use a programming language to describe data? • AutoCAD(PRL) / ProEngineer (Princeton) • very detailed, but slow • good for detailed design and engineering phase
Advantages of VRML • Standard (non proprietary) • Readily available and fast on low cost hardware • no dongles! • Viewers are cheap (free?), multiple vendors • Transfer from professional packages (to?) • Designed to be written by people/machines • Editors/Creators not essential for this application Many good books available, most on WWW Documentation:
Example 1: 3D Magnet Concept simplest interface from design codes (C++, FORTRAN, IDL) to 3D viewer. Initial IDL 3D widget viewer used for years, but poor navigation lacked depth cues static image almost meaningless (presentations)
Lowest effort VRML model require only list of [(x,y,z)(x,y,z),...] “cylinder” element (VRML 1) using DEF messy - needs orientation, bad meshing “Extrusion” model under VRML 2 perfect fit to requirements
Sample of VRML 2 a sampling of “nodes” in VRML 2 (from extrusion solution)
First attempt (VRML 1, DEF) very clumsy, but works (see fig on 1st slide)
part of plasma shape design process magnetic surfaces exist in plasma colour code “bad” and “good” “curvature” etc on surface use shading to provide 3D cues high order rendering varying hues ( physics) varying light intensity( shape) Ex2: Evaluation of Plasma Shape
First, the uncoded surface relatively few facets required Color per facet light shading is easy Color per vertex light shading (on most systems)
IndexedFaceSetSee notesin handoutcoordsface indicescolourtablemap coloursto facesReplicatefor secondperiod
Gouraud colours AND shading 7000 facets Bu (theta contravariant cpt)
Level of Detail - Object Hierarchy complexity increases on close examination helps retain information about sub parts LOD examples
Future Work Add AutoCAD->VRML (3D Studio?) nodes at the highest level of detail (LOD) Add switches to control lighting, LOD, colour/vertex or facet.
Conclusions work in progress... success depends if physicists find it useful speed - gl accelerator boards look promising beyond viewing…. is the simple collision model useful to “test fit”? is the scripting language powerful enough to program over inadequacies?