Non-manifold detection

I’ve created a model that I was getting ready to 3D print.
I’m getting a warning :warning: in the slicer software (Lychee) that the STL is non-manifold, and I cannot find what might be causing the error in the original model created in Shapr3d.

I know that if you are in the process of modeling a feature in Shapr that is non-manifold, it will give you an error message. I don’t recall that happening though.

Is there any tips or tricks to find non-manifold geometry?


For starters, is the body you exported one solid body? Meaning, it not composed of more than one body that have yet to be UNIONED as one.

@TigerMike yes, I did verify that it is one body.
A couple days ago it wasn’t because I did not know it would be an issue, so I tried it as one complete union, still no luck.

Part in question.



You moved the body and there is nothing else that exists in that space? Try making it transparent and look for internal anomalies?

Try splitting objects/parts in Lychee and see if something reveals itself.

@Oregonerd I guess I can split the part into multiple pieces, import them individually into Lychee and see what body has the problem.

And yes, there are no other bodies.

A good tool for checking manifold issues is MeshMixer. It has an analysis mode where it will identify non-manifold and other issues.

@TheBum thanks, I’ll give that a shot.

@TheBum It totally worked great, thanks!

Turns out there was a surface non-manifold issue AND a hole issue, that I NEVER would have found.

One click and both were fixed. I imported them into the slicer and the errors are gone :+1: :+1: :+1:


@NathanD where in the model did you find the non-manifold issues?

@Istvan_CEO_Shapr3D these were the errors pointed out in mesh mixer.

I then went back into the model in Shapr, searched, and found it.

This is what I found viewing “inside” the part.

Like I said, I would have never found it. :woozy_face:


How did you rectify the last one?

@Oregonerd mesh mixer has a repair function for the mesh body. One click fix.

I have not tried to fix the Shapr model.