this is kind of… hard to describe, really, since i don’t know all the conditions to this, seems random at times…
basically what happened is, i inserted a meshpart, uploaded a mesh and applied the texture. inserted a part and into it, a specialmesh. pasted the texture onto the specialmesh, and as soon as i pasted in the mesh ID, both the Part and MeshPart disappeared. their physical form was still there, but they were completely invisible. i tried reuploading variations of the mesh but it kept getting the same problem. pasting the part with specialmesh into a new window did nothing to help me.
then, i decided to clear the texture from the specialmesh, and the meshpart (and the part with placeholder “filemesh” specialmesh) became visible. filling the mesh field back made both parts become invisible again. dragging the part with specialmesh made them both become visible somehow, but both disappeared instantly after i released the mouse
similar thing happened before with a different mesh but it did not hide the original meshpart if i recall…
i ended up scaling it up just a little bit and exporting one more time and that fixed the issue, that was the only change after the previous… corrupt? mesh uploads… but the fact it DID appear in the studio a few times with the broken meshes really confuses me
SpecialMeshes inside MeshParts are not supported by the engine. You should expect to see undefined behavior when doing this. I recommend either using a MeshPart on its own, or a regular part with a SpecialMesh.
If you do think this kind of hierarchy should be properly supported (SpecialMesh inside MeshPart), please file a feature request with your use cases and expected behavior!
the specialmesh was inside normal part, not meshpart. why i mentioned meshpart so often is that it was also affected after i copied the mesh ID from it to the normal part despite me not doing anything with it. it existed simultaneously, separately
deleting the Part seems to make the meshpart visible. while testing if it is still occurring before i applied textures (after delete and undo) not only did both objects become visible at once, but dragging one of them to different location, they both and also a meshpart with entirely different mesh ID disappeared. couldn’t get both objects to stick with delete and undo after applying the texture though
