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Multipart objects in 3MF  

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Gauthier
(@gauthier)
Eminent Member
Multipart objects in 3MF

From what I've gathered, STL is the old format, and 3MF is what I should prefer to use, in these modern times.

Some of the designs I make are multi-objects, and I have PrusaSlicer setup with a virtual extruder, I do manual MMU, so to speak.

Importing an STL file into PrusaSlicer works fine, that parts are placed correctly relative to each other, as in my CAD program. This does not work with 3MF though, the obejcts all get snapped to the build plate.

Is this a problem inherent to the 3MF format? Is it PrusaSlicer who doesn't deal correctly with multiparts from 3MF? Is it my CAD program (onshape) that exports wrong to 3MF?

Posted : 06/09/2023 8:17 am
Neophyl
(@neophyl)
Illustrious Member
RE: Multipart objects in 3MF

A single stl that has multiple parts is still a single object. So the lowest part is placed to the bed and the other parts keep their relative positions. If you were to use the split to objects function in PS after it’s loaded then all those newly separated parts would all drop to the bed. The rule in PS is that ALL `objects ‘ must touch the bed. 

A 3mf made of multiple objects is brought in as multiple objects. As such each object has to obey the object rules and is placed on the bed. You would have to combine/join the parts in your cad software prior to saving as 3mf to let them be counted as a single Object like a stl is when loaded. 

Posted : 06/09/2023 3:47 pm
Gauthier
(@gauthier)
Eminent Member
Topic starter answered:
RE: Multipart objects in 3MF

Thanks. Do you know if 3mf support multiple parts to a single object? 

Posted : 06/09/2023 4:49 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Multipart objects in 3MF

It’s not if the format supports it, it’s if your design software does I think. The format should as when you save a project in PS (which is a 3mf file) then any objects you have combined are saved that way. So yes a 3mf file can save a multipart object. 
You will just have to figure out what’s required in your cad. 

Posted : 06/09/2023 5:16 pm
Norro
(@norro)
Member
RE: Multipart objects in 3MF

tbh that sounds like a fault in PS trying to be overly helpful and messing up what you intended to do. This is why people hated the paperclip.

You should always be able to override and just leave it how it was.

Posted : 29/12/2023 9:50 pm
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