Non manifold faces


#1

The object looks fine, but when I run it thru mesh lab, it shows non manifold faces. Note that I tried a simple rectangle with a bend and saw how you must be careful with a bend, but thought I fixed the bends?

Jerrynormandnewtab.skp (97.6 KB)


#2

When I used the mesh lab feature to remove faces from non manifold edges, it appears to have corrected the problem?

Jerry


#3

Why did you run that check to start with? There are a number of other cleaning filters you probably have to run now that edges are deleted. Do a search there are a whole series of YouTube videos by Mr. P showing how to clean a model?
Looking at you model above what are you trying to do? Make a sheet metal items so you can bend/ develop it?
If that is the case just draw it Su has a plugin that that will develop for you even with the tabs.


#4

I wonder if the problem comes from reversed faces in your model. I changed the back face color to green to emphasize them:

After correcting the reversed faces, I exported as stl and opened in Meshlab. It merged some duplicate vertices but didn’t say anything about non-manifold faces and displayed this:


#5

Hi,

Does that mean I pushed when I should have pulled? How did you know that the faces were reversed?

Jerry


#6

Hi,

I am a newbie and did not even know that a "completed " object could still have problems when trying to 3d print. :frowning:
Jerry


#7

What will help you identify this is to make inside and outside faces obviously different. You can change to what suits you…


#8

If you change the View mode to Monochrome and give your Style a distinctive back-face color [here green] you can readily see reversed faces. Select them and use the context-menu item to reverse them. All faces should be consistently oriented with the off-white front material looking outwards.

There’s also a tiny loose edge drifting off…

Because your form was made from 5 separate ‘slabs’ where they intersect there are internal faces.
Cut a temporary section through it and delete all of those internal partitions…

A manifold solid can only contain geometry - edges and faces.
Every edge must support exactly two faces.
So no faceless edges, no edges around holes or forming shelves of flaps, no internal faces where some edges will have three or more faces etc…


If you select your geometry and make it into a group and work within an edit of that, the group will be shown as ‘solid’ in Entity Info’s header IF you fix it.


#9

You can try my Solid Inspector extension to assist in identifying issues when creating manifolds in SketchUp: https://extensions.sketchup.com/en/content/solid-inspector²


#11

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