More information required on 3MF

Hi could you help out with more information on using the customisation of 3MF.
Where should one even start with setting of the tolerances, will a finer tolerance mean the print will take longer etc. what is meant by the hidden items, saving each first entry level, what does all this mean, where can I read up on these various settings.
All round more information is needed please

Hello! Great questions, let me help you with them.

When you export a CAD model to 3MF, the mathematically accurate CAD model will be converted to a mesh file. Mesh files are defined by small planar faces called polygons, they do not have any curved edges or faces so there will be some data loss during the conversion. What looks to be a smooth curve on a mesh file, in real life is a group of pretty small polygons. Even though they are still planar faces, each of them is so small the surface looks curved.
When you set the resolution, you basically define the tolerance that is applied during the conversion. The tighter the tolerance, the smaller the polygons will be, resulting in a smaller deviation from the original CAD model.

When you export a Shapr3D design to any other file format, normally the shown objects will be exported. If you select the Include Hidden Items option, the hidden bodies will also be exported.

Saving each 1st-level item separately is useful if you regularly use folders in the Items List. In this case, if you have Body A in the items list, create Folder B on the same level and put Body B into Folder B, Body B became a 1st-level item. If you check the option, Body B will be exported in a folder called Folder B and the output from Shapr3D will be a compressed file.

I hope you’ll find these useful,

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Hi Peter
Thank you for the reply, I get and understand the first point, but as I asked will setting a finer tolerance lengthen the print time. Also is there a limit where even setting the finest tolerance the particular printer may not even handle the extreme range of tolerance?

To understand the other two points I think I will need to experiment taking items from Shapr3D to Chitubox, as I kind of get what you are saying but I will need to see how it actually functions.
Cheers Alistair

Print time mainly depends on the print settings, not the allowed deviation of the exported model. By setting the tolerance between reasonable values you’ll not change the overall geometry that much it could affect the print speed.
Let’s say with 0.01 mm deviation a cylinder will be converted to a 40-sided polygon instead of 0.02 mm which would result in a 28-sided polygon. However, if you set the tolerance to 5 mm, the cylinder will be exported as a rectangle which is a significant change in the geometry and will result in possibly faster prints with definitely worse quality compared to the original geometry.

Theoretically there is no limit for the allowed deviation, but you should keep an eye on efficiency. A super tight conversion-tolerance results in an incredibly fine model that has a huge file size which may be fine (but not particularly necessary) if you are using a resin printer. On the other hand, well-built FDM printers may be in the field of 0.1 mm accuracy whereas a thousanth of millimeter is a pointless value of tolerance.


Thank you Peter, that is an excellent explanation, now that brings that together for me, understanding how that works much better now.
I shall investigate the topic further with my own examples

Do you know if 3MF uses T-mesh? Quads or Triangles?

Found this. (Also of note: Prusa slicer has profiles for other printers besides the Prusa brand.)

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