At the moment the GDML workbench handles GDML materials and does not try to resolve with FreeCAD materials.
I would like to see if there is a better way than just keep them seperate?
A good source of reference for GDML materials is https://www.ge.infn.it/geant4/training/ ... pliDev.pdf
Geant4 & ROOT users can make use of NIST database for Materials see https://www.nist.gov/programs-projects/ ... repository
For details on FreeCAD materials I am aware of https://wiki.freecadweb.org/Material
I have had a look at Materials.py in the Materials Mod but not sure how I could add a material definition under program control when importing a GDML file, or dynamically updating the Materials Dictionary.