Overview¶

Objective ¶

Convert a Geant4 geometry into a surface based STL file format for use on GPUs.

reduce to the simplicity of a bunch of triangles
two material indices, inside+outside for every tri
sensitive detectors, handled via a special material index
optical surface properties, presumably can be handled via material index
if 2 materials/colors per tri not supported
- copy and flip faces to provide a place to attach the 2nd material ?
- pack both materials in the place of one ?
- does this have to get collapsed down to 16 bits in STL later anyhow ?
originating volume identity, probably not needed (but useful for development)

DAEFILE: Extraction of relevant parts of VRML2FILE visualization from Geant4, enabling creation of libDAEFILE.so
xdaefile: Geant4 main executable xdaefile that uses libDAEFILE.so to read a GDML file and export WRL (and maybe DAE)
DAE: Extraction of relevant parts of GDML persistency writing from Geant4, enabling creation of libDAE.so. Starting from cp -R /data1/env/local/dyb/external/build/LCG/geant4.9.2.p01/source/persistency/gdml DAE
xdae: Use of libDAE.so

detdesc: source xml
geant4: in memory tree of PV+LV+Solid instances
gdml: xml persistence, with model close to geant4
vrml2: visualization targetted, a list of shapes each composed of triangle/quad faces and vertices
x3d: later incarnation of vrml2
stl: triangles only, normal + 3 vertices + UINT16 per-tri color http://en.wikipedia.org/wiki/STL_(file_format)
collada: widely supported (including OSX SceneKit, Xcode, Preview), flexible http://en.wikipedia.org/wiki/COLLADA http://collada.org/