Is your feature request related to a problem? Please describe.
In our experiments we are using detectors and passive elements with complex geometries that we need to convert into ROOT geometries to run our simulations, for example the GLAD superconducting magnet.

Describe the solution you'd like
Is it possible to perform this conversion using FairSoft/FairRoot?
For instance, if we use CADMesh to convert STL files into ROOT geometries, can we then load these geometries with the FairRoot classes to run our simulations?