When exporting to stl, facets are added to the model deforming the object

Hi everyone,

I am new to the forum, but maybe you can help me. I have to print a very simple box in 3D but for some reason when exporting the file there are facets added which don’t belong there. I’ve tried to build the box in multiple different ways, using different commands, but it always ends with a weird stl file. Does anyone of you know why this happens?

Hello - please see



I’ve exported quite a few .stl’s from Rhino for 3D printing, and I’ve not had many problems.
Did you mesh the object before exporting to see what you have?

An export-import thing could happen on either end. You could also inspect the mesh with Meshlab: https://www.meshlab.net/

Thanks a lot for both of your answers!

In one of the links of Pascal, I found this:

This was definitely helping a lot! All the facets which where created on the edges disappeared. So it looks now like this:

There are still some mesh problems on the edges, that I tried to regulate in the mesh preferences but I couldn’t manage. Brenda do you think this could be solved by mesh lab? Or is it not important referring on the second link of Pascal?
In the end this container will be SLS printed in transparent and should have a really smooth corners, as the box consist of more components which have to fit perfectly and will be seen through.

It’s truly amazing how quick people help on this platform, thanks for that!

Meshlab will not increase the resolution of the STL file, you will need to do that from within Rhino when the STL is exported.
You can modify the values in the dialog box to increase the resolution. Be aware you can easily create triangles smaller than the printer resolution, so having more triangle will increase the file size unnecessarily as it will not improve the printed result.
You can change the values and then hit “Preview” to see how the triangulation is affected.