Imported .stl files creating stuck tracks

[weller]

@james.pollock

Out of curiosity though how could oddly shaped triangles create issues with geant4?

could be some algorithms to calculate distances/directions. I had a similar issue:

Cadmesh: Sample point is not on the surface

The reason of the issue is the calculation error of the algorithm for calculation of a distance from a point to 3D triangle. In your case the error very often was bigger than the thickness of the surface, it resulted in incorrect return value from Inside(). To fix the issue you can change the code for the region 0 in G4TriangularFacet::Distance(p) (line 346) to the following: // // We are in region 0. // G4double dist = fSurfaceNormal.dot(D); fSqrDist = dist*dist…

@james.pollock

It could be the case, do you know of a program I could use to check this or revaluate the mesh with more regular triangles?

I would try MeshLab and use the filter “Remeshing: Isotropic Explicit Remeshing”. You will have to play with the parameters to get the best results…