feature, calculate RadiationLength and NuclearInterLength

[zhaozhiwen]

It would be nice to add a feature to calculate RadiationLength and NuclearInterLength along certain path.
Maybe shoot geantino and use G4Material::ComputeRadiationLength and G4Material::ComputeNuclearInterLength() to sum the materiel along its path.
I wonder if checking overlap is done in a similar way. If so, it can be expanded easily.

[mholtrop]

Checking overlaps used to be done by shooting "rays" through the geometry, like you are thinking. That was before 4.10.0. Now the checking of overlaps goes through the entire tree of objects, and for each object checks for 10000 points on the surface whether there is an overlap. The new method is far more robust. The old method could miss a small volume unless you used a tremendous number of rays.

For what you want, I would assume that you are only interested in the radiation length along a particular path, not all paths? I think implantation here would depend on the usage case you have in mind.

[zhaozhiwen]

Maurik, (I somehow never replied. sorry ) yes, I am thinking about shooting "rays" through the geometry. so if I guess it's not easy after 4.10 then