Help with G4ExtrudedSolid

Geometry, Fields and Transportation
1

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_Geant4 Version:_10.1.p03
_Operating System:_Centos7
Compiler/Version: 4.8.5
_CMake Version:_3.17.5

I can’t work out how to use G4ExtrudedSolid. Whatever I try it fails with the message “making facets failed”. A simple example to get me started would help. This is what I have tried.
float stepDepth=171.35;
float stepY=167.0+stepDepth;
float stepX=260.0;
G4TwoVector off1{0.0,0.0};
G4TwoVector off2{0.0,0.0};
std::vector polygon{{0.0,0.0},{0.0,stepY},{stepX,stepY},{0.0,stepY},{0.0,0.0}};
auto step=new G4ExtrudedSolid(“Step”,polygon,stepHalfLength,off1,1.0,off2,1.0);

2

Try:

std::vector polygon{{0.0,0.0},{0.0,stepY},{stepX,stepY},{stepX,0.0},{0.0,0.0}};
3

No difference. I get the same error message.

4

It works if I take of the final {0,0}

double stepHalfLength=925./2.0;
float stepDepth=171.35;
float stepY=167.0+stepDepth;
float stepX=260.0;
G4TwoVector off1{0.0,0.0};
G4TwoVector off2{0.0,0.0};
std::vector<G4TwoVector>  polygon{{0.0,0.0},{0.0,stepY},{stepX,stepY},{stepX,0.0}};
auto step=new G4ExtrudedSolid("Step",polygon,stepHalfLength,off1,1.0,off2,1.0);
5

Correct. In a polygon, the last point is connected with the first one. Before deleting, point {0,0} was duplicated. This caused a problem with polygon triangulation. The problem was fixed in Geant4 10.03. So, I would recommend you to migrate to recent version of Geant4.