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STL export orientation

Posted: Mon Jan 21, 2019 7:27 pm
by jweather
I just printed a lovely Snub Cube via the STL Export and my 3D printer. I'm looking for other interesting shapes to print now, and came across the Small Snub Icosicosidodecahedron (too ambitious?). My problem is getting it to set on a flattish face for printing -- preferably the 3-way symmetry axis (6-pointed stars).

No matter which axis I select for "sit on", the STL export seems to have the same orientation (up on its points). I tested the STL Export with a simple cube and can easily set it up on its point with "sit on 3-fold" or flat with "sit on 4-fold". Is there some reason this isn't working with the more complex shape? I also tried selecting a face and "Sit on current face/edge/vertex/symmetry"

Thanks,
Jeremy

Re: STL export orientation

Posted: Tue Jan 22, 2019 2:30 pm
by robertw
Try using look-at instead of sit-on. The problem is that Stella exports a model with Y up, whereas some STL software uses Z up. I should add an option for this some time. In the meantime, using look-at instead of sit-on fixes it.

Re: STL export orientation

Posted: Tue Jan 22, 2019 6:27 pm
by jweather
That worked perfectly for orientation, thank you. I'm still trying to get my slicer (3D printing CAM software) to recognize it as a solid object, but I haven't exhausted my possibilities there yet.

Here's a rhombicuboctahedron, snub cube, and part of a small snub icosicosidodecahedron: https://imgur.com/a/a2c7qj5

Re: STL export orientation

Posted: Tue Jan 22, 2019 8:30 pm
by jweather
In case anyone else is export STLs for 3D printing, the magic incantation to get Cura to read the STL correctly was:
- repair it in Microsoft's 3D Tools: https://tools3d.azurewebsites.net/
- import the resulting 3MF file into Autodesk's MeshMixer, and export as ASCII STL

And the results: https://imgur.com/a/UI5gzUO

Thanks again for an incredible program, Robert!

Re: STL export orientation

Posted: Wed Jan 23, 2019 5:13 am
by robertw
jweather wrote:
Tue Jan 22, 2019 6:27 pm
I'm still trying to get my slicer (3D printing CAM software) to recognize it as a solid object
You can probably fix this by exporting from the stellation view rather than the base view.

Polyhedra like this with intersecting faces will be exported with intersecting faces, and some slicers can't handle that.

The stellation view shows a model that consists only of the externally visible parts. If you export from here it should be accepted without any other processing.