That's because that part has an invisible plane mesh which gets voxelized. If you're using my fork, add @PART[<part name>]:AFTER[FerramAerospaceResearch] { @MODULE[GeometryPartModule] { %forceUseMeshes = True // just in case %ignoreIfNoRenderer = true // skips voxelizing invisible meshes } } Currently voxelization works as in the original FAR with a few extra options, haven't made skipping invisible meshes default yet.