I used check objects, SelBadObjects, Edge analysis all give valid object result. When I bring it into the slicer, it finds “Non-manifold” edges which it fixes. Any thoughts on this? Is it Rhino/slicer/my modeling?

Maybe try to create a mesh via the mesh command before the export. If your slicer works with meshes this often helps. Sometimes the export command mesh behave not optimal for some objects. The creation of a mesh before give you more control about it. Try some settings to get a real watertight mesh. Sometimes it also helps to export an 3mf instead of an Stl

@CalypsoArt please post a 3dm file of the (poly)surface in question. a polysurface with manifold edge(s) can be valid / not being bad. [Screenshot 2026-11-07 at 22.35.14] use _showEdges with option non-manifold _what and see this section: Geometry: Valid polysurface. non-manifold polysurface with 6 surfaces. it still might be an meshing issue… but only guessing - upload the file and I am happy to help - cheers - tom

Thanks guys. I’ve gotten this before. I do export everything as .stp and bring that into the slicer. However, this only happens on occasion. TEST_RYOBI_TOOL_HOLDER_FLAT_01.3dm (11.0 MB)

The NURBS model you uploaded does not have any non-manifold edges. Can you upload the .stp file?

you have some artefact here at the (x) (and at other positions as well… [image] [image] you can mesh the polysurface in rhino then _showEdges choose none-manifold and zoom EDIT: it s those 4 spots that need cleaning: [image] the mesh still looks suspicious - but no non-manifold edges anymore: [image] TEST_RYOBI_TOOL_HOLDER_FLAT_01_tomP.3dm (1.7 MB) uploaded without mesh becouse of size limits… EDIT2: … just to say - as fare as i know, most slicer-algorithms are based on triangulated mesh-data. so first thing the slicer is doing - it will mesh your geometry. do the meshing in rhino will give you more controll then for example importing a .stp in bambu studio or prusa slicer.

Some definite potential problem areas in this model. 12 faces with areas of 0.005194 or less: [image] 16 edges with lengths of 0.005246 or less: [image] Potentially problematic when meshing dependent on tolerances and mesh settings. -Kevin

I had seen information that a .stp was a better base file to slice so I always uses that. Is that wrong? I understand that the slicer converts to mesh, should I just be creating.STLs for slicing out of Rhino? [image] Kevin: Some definite potential problem areas in this model. 12 faces with areas of 0.005194 or less: How are you getting those error points to display? How would I fix them?

[image] CalypsoArt: the slicer which slicer are you using ?

Elegoo Slicer. Which is a fork of Orca, which is a fork of Prusa. I print on an Elegoo Centauri Carbon 1 so went with with the slicer it came with. (when I print from my Linux Mint machine I use Orca) The CC1 has been flawless these last two years.

i never did a precise research… but i googled a bit: taken from Release notes of PrusaSlicer 2.5.0-beta1 (August 2022) And I strongly doubt this has been changed. (But I might be wrong)

Rhino says model is good. Slicer finds "Non-manifold" edges

Rhino Rhino for Windows

CalypsoArt November 8, 2026, 8:31pm 12

Thanks, but I’m not sure what that means? That the slicer step to mesh is problematic? Should I create the mesh in Rhino after the model is completed?

Request - Show Short Edges

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Rhino says model is good. Slicer finds "Non-manifold" edges

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