MS Powerpoint only accepts the following file types :
- 3D Manufacturing Format: 3MF
- Filmbox Format: FBX
- Object Format: OBJ
- Polygon Format: PLY
- Stereolithography Format: STL
- Binary GL Transmission Format: GLB
With FreeCad, colour your objects to the required colours.
Use FreeCad 0.18 to export the selected 3D model to Wavefront *.obj file which will include a *.mtl file automatically.
Import the *.obj file into Blender 2.81a and export the selected objects to glTF 2.0 *.glb.
Just import the final *.glb file into MS Powerpoint and you can rotate the object in any way you want in your slide.