I have this model, for instance, made in www.TinkerCad.com. It is made up of a bunch of grouped objects. I'd like to be able to back it up by saving it locally, then reimport it and ungroup those objects on the imported model. Is there any way to do this?

(Note: my motivation is permanent backup of my important models. TinkerCad deleted a few million accounts in May 2021 it looks like).

When I export a model from www.TinkerCad.com I get these options: .obj, .stl, .glb. enter image description here

No matter which I choose for export, if I reimport what I exported, it is now one solid piece and it appears I cannot ungroup its elements to edit them anymore.

Also, if someone else opens up my .obj file in some other tool, like Fusion360 or Solidworks (neither of which I can use right now since I'm on Linux and don't have a license for Solidworks), will they be able to edit the individual components of my model like I did in TinkerCad to build it in the first place? (I think this is NOT possible on .stls, no?--but I don't know about .obj files).


1 Answer 1


STL and OBJ are formats that define a surface through trigons and a waveform respectively - to make the export work, TinkerCad runs a boolean union operation first. Without this, it would run into the problem of having bad surface geometry - a flaw that happens still when the boolean joining fails properly.

GLB is a container for gITF files and can store file hierarchies as well as cameras and animations. However, even if the structure would allow having all the bodies, TinkerCad does run a boolean union before it.

As a result, you'd have to physically separate parts of the item that are not to be joined from one another as in an explosion diagram. That way the boolean union would result in each part being separated and exporting as separate shells.

Separating Shells into models

If you have an item from TinkerCad that has multiple separate shells, you can open the STL or OBJ in a program like Meshmixer and run a Separate Shells operation. Then you can export the parts from that program as separate files that can be imported into other CAD or 3D-Design software - or sliced directly.

Re-CADing the models

If you have your parts exported and separated, it would be very beneficial to properly CAD them in a program that allows STEP files. For this you'd simply import them into a program and use the 3D Model from TinkerCad as a model to design around.

Fusion360 does allow to import STL and OBJ as a mesh, though isn't the best to edit it.

FreeCAD, an open-source alternative, does allow the import of STL and OBJ too and has a Linux distribution.


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