Modelling an arbitrary or complex geometry

Hello, I am looking for suggestions and/or pointers regarding importing an arbitrary geometry. In the simplest case this would be importing an x,y,z table where each cell corresponds to material with a certain density. I realize I can stack many boxes but maybe there are smarter ways to go.
Thank you!

Hi, you can build complicated models and load them in Geant using GDML, take a look at the advanced build options and also to this example examples/extended/persistency/gdml.

yes thank you. Looks like gmdl files are created from some open source version of CAD. That is valuable but unfortunately is not useful/practical for my application. Thanks,
-t