J3DBmt
J3DBmt is a tool to import and export data between BMD and BMT formats. BDL models can be used as well. This tool was originally created to make things easier when importing models from Super Mario Sunshine, as the BMT format doesn't seem to work for the Super Mario Galaxy games.
Commands
To extract material data from a model file, use
J3DBmt.jar -e inbmd.bmd outbmt.bmt
If you want to import material data into a model file, use
j3DBmt.jar -i inbmd.bmd inbmt.bmt outbmd.bmd