Converting to STL for printing created new and bad geometry! Help!

Hello Out There,

I’ve been working on an enclosure to print, and when I export it to an STL, I get some weird and broken geometry. I’ve attached images here. I’ve opened it up in Fusion 360 and my printer software, so I’m confident that the error is there.

Thank you!

In Rhino Windows when exporting to an STL, there’s usually an additional detailed dialog box that asks about density, angles and ratios. Haven’t checked what Rhino OSX defaults to, but you might want to try zeroing everything out as shown in this post

I used to get the same wonky meshes when Rhino 4.0 had those fields populated with something else.

This looks like bad export mesh settings, as what you are seeing on the screen in you lower image - the original - is also a mesh created exclusively for display purposes. So there is no reason why the quality of your part should be any worse than what you see in your lower image - certainly not as bad as the upper mesh image, which looks VERY coarse.

If you can, post your original file and the mesh settings used to generate the STL. Also, have a read here for more info on meshes in Rhino.


First, is the object “watertight”?

(You may know this, but if not type “ShowEdges” to check. If there are any “naked edges” then these need to be repaired first.)

Second, I’ve found that a slightly more predictable workflow, rather than exporting to stl, is to first do Mesh > From Nurbs Object. This allows one to easily preview various levels of mesh density, rather than an automated conversion taking place. In your case, I’d simply set the highest level (for now), then saving this as an STL to see if you have the same issues.