You can move, rotate, or scale the 3D model by rewriting MatrixFactory.h. You can save the screen as bitmap file to SD card by enabling bitmap_out in M5Stack_MMD.ino ...

This API uses the Open Asset Import Library (AssImp). A list of supported model formats can be found here. SuperBMD.exe can be used to convert models to the BMD/BDL formats, or to convert BMD/BDL ...