[BUG] Importing/Exporting STEP/STL

[jgauthier]

I don't know there issue lies, so my title is vague.
Steps to reproduce:
I have imported a STEP file. (attached)
I removed 5 of the distinct objects in it. There are 6 and I'm only interested in 2. So, I retained the two in the "middle" of the file. I did this one at a time so I would end up with 2 distinct STL files afterwards (for 3D printing)

I exported the remaining object to STL.
I opened the STL in a 3D Slicer.
The slicer shows a single layer is completely missing.
I tried this in another slicer and found a different issue.

I reproduced this scenario with Fuision360 and did not experience an issue with the slicer and the STL file.

That said, I do not know if is the import of the STEP file where the issue lies, or the export of the STL file. But, I've included everything here.

The zip file contains the original step file.
The freeCAD file contains the singular model with the the issue on of the the "middle" objects from the step file.

Lastly, this the results of the imported STL into the 3D slicer (prusa slicer)

2021-06-18_17-41-33.png (182.12 KiB) Viewed 884 times

And this is the result of importing the file into Cura.

2021-06-18_17-42-18.png (151.49 KiB) Viewed 884 times

I am using FreeCAD 0.19.2. If there is anything else I can do to help with the scenario I will.

[Roy_043]

Part_CheckGeometry reports many errors. So the Step file is the cause of your issues.

[jgauthier]

Okay. I ran through every single "validation" check in Fusion360 and it did not reveal any issues.
So, I don't know.

[Roy_043]

The geometry on the inner curve of the pipe looks weird IMO. There also seems to something wrong with the edge of the teeth. It may be worth experimenting with the "Angular Deflection" and/or the "Deviation" of the object before exporting to STL. Or you can try creating a mesh with Mesh_FromPartShape and exporting that (after checking it with Mesh_Evaluation).

[Tek3D]

One surface clearly has a hole in it when importing into freecad and in fusion it doesn't. Some fillets are also missing.

step import - Copy.jpg (116.29 KiB) Viewed 821 times

[jgauthier]

Thanks! I really don't know fusion enough to do much. I appreciate you doing that!

[Tek3D]

Thanks! I really don't know fusion enough to do much. I appreciate you doing that!

No problem, unfortunately I don't think this is easy to solve. I'm assuming it's an issue with the open cascade step translator, so this may just be a case of it is what it is.