Preprocessing of 3D CAD files for Keras Conv3D input
I found a way that works now.

Keras Conv3D can be fed with a numpy array of the voxelization and the corresponding class of the file.

So first the files have to be voxelized with a tool like binvox.

Afterwards those files can be read into a numpy array with binvox-rw-py:

np.int32(binvox_rw.read_as_3d_array(f).data)


In combination with the classification, the files can be used as input for a Conv3D layer in Keras.

A complete example can be found here.