Cad Imports: coming soon

Preparing a mesh for import? Heavy or non-watertight CAD meshes can be simplified and repaired for Geant4 with the Cure Mesh utility (gemc-cure-mesh), which decimates, welds, closes holes, and re-orients facets so the tessellated solid loads fast and without warnings.

Sensitive CAD volumes and detector dimensions

A CAD volume is imported from a mesh (.stl / .ply), so it has no native Geant4 solid and therefore no constructor dimensions. For native solids (G4Box, G4Tubs, …) GEMC exposes those dimensions to the digitization stage — a hit-process plugin can read them back through GHit::getDetectorDimensions(). For a CAD volume that list is intentionally empty: the mesh has no width/height/radius to report.

This matters when a CAD volume is made sensitive (it is assigned a digitization). Such a volume still carries its full identity (the gidentity string, e.g. sector: 1), and hits are collected normally, but a digitization plugin must not rely on getDetectorDimensions() for CAD hits — it will receive an empty vector. Derive any per-element geometry the plugin needs from the identity or from the mesh itself instead.