I’m sorry if that topic have already been covered, but I couldn’t find it.
I’m wondering if there is an extension or a good trick to find edges connected to 3 or more faces.
This is a struggle I sometime have when making solids. Solid inspector does a hell of a job to highlight solid problems, but it’s only blindspot I know of is when the geometry is closed but non-manifold.
In my eyes that’s a perfectly understandable closed volume, but SketchUp won’t treat that as a solid.
So I’m left searching the model manually and that can be tedious, or nearly impossible sometimes.
Selection toys can filter “open edges” for exemple. Could there be some tools that filter “edges connected to more than 2 faces”?
Get both Solid Inspector and Solid Inspector 2 from the Extension Warehouse. Use them to check for problems with your objects.
Set the Face Style to xray so you can see inside when you run the extensions. With a little practice you’ll be able to discern internal faces just by looking at the model in xray.
Thanks for your quick reply!
I think I see what you mean. And indeed, X-ray is all I go for when running solid-inspector. But I’m talking about this one problem that is not actually covered by solid inspector. The case of the non-manifold-but-closed polysurface.
From observation, SketchUp will only accept as a solid a geometry where every single edge is connected to 2 faces. The moment an edge is shared by more than 2 faces (usually 4), the group loose it’s solid status. But solid-inspector don’t mark that edge as a problem.
A simple screenshot would do a better work than my explanations here. I’ll try to make a quick one as soon as I reach a computer!
The only difference with your exemple is that the geometry is connected from below, so that’s one single volume. No exterior face to speak of, but still this very problematic edge in the center
So to Sketchup that’s a non-solid group:
Yes!
I wrote 'Solid Inspector' and not 'Solid Inspector2' (as in your screenshot). And if you click on ‘Solid Inspector’, it will take you exactly to the extension to download.
I just thought Solid-Inspector 2 was the updated version of Solid-Inspector.
Thanks a lot to you, and thanks to @DaveR who told me the same and I couldn’t understand xD
FWIW, the reason I suggested both extensions is that they work differently. Sometimes one will catch problems the other doesn’t.
What you show in your images is often referred to as a bowtie. There are four faces sharing a common zero-thickness edge. In reality this couldn’t happen. As a single object it would need to have some thickness along that line or there would need to be a gap. Which one depends on what you are really modeling.
Also, as you get used to modeling for 3D printing you should be able to recognize issues like that and prevent them or fix them without needing the inspectors. You’ll also learn to recognize and avoid the other things that prevent groups/components from being solid.
@DaveR Yes, I understand now why you specified SI1 and SI2. For some reason I initially read through your post without noticing your very explicit mentionning of the 2 of them.
I didn’t know this “bowtie” word! Is it because there is a similar pinching stress point
Coming to 3D prints, I wish I were modeling them from start! Too often I have to work from existing models.
But this need for a solid isnt just for 3D print:
Measuring volume of earth on terrains, volume of air in rooms…
And sometime just for using the solid tools while modeling.
Thanks again for your help, that will make my life easier!
No. In reality you could not make anything that has a zero-thickness intersection. Remember that faces and edges in SketchUp have no thickness. Again, you would have to create some thickness there or leave a gap. If it was two cubes they would each have their own edge and the closest you could get them is next to each other.
That can be a problem.
Understood. Consider that the situations you show in your images couldn’t exist in earth or air either.
Got it, the infinite sharpness of all these boxes edges isn’t physically possible. And so does their perfect overlapping
Indeed as you describe, I end up separating them or giving them thickness.
