How to check N-gon with holes?


In my workflow I export sketchup files to other softwares that dont t support ngon with holes unlike sketchup. So I need to manually draw line to remove thoses holes.

But scouting thoses ngon with holes is difficult, is there’s a way inside of sketchup or with an add-on to Easley find thoses ngon ?


A sample model, or at the very least an image, showing these ngons would go a long way to helping us help you.

First image : This is how regular 3D software handle holes

Second image : this is how sketchup handles ‘ngon with holes

Third image on the left it’s a regular ngon, on a right it’s the procedure you need to do in sketchup sobthat the ngon is not triangulated like crazy when exporting to other soft !

But you triangulated it?

no i want no triangulation at all, that’s why im asking if there’s a plugin in sketchup that can detect thoses special faces, so that i dont have any triangulation at all when exporting.

i just need to do this and everything will be exported fine

what exporter or importer are you using for what destination app…

the chances are the problem lays with that process…


.obj to blender, blender don’t support ngon-with holes yet, so i need to create regular n-gon firt in sketchup before exporting, im just searching a way to make this process more easy by maybe a sketchup plugin that can detect thoses types of faces ?

I agree with John (@john_drivenupthewall) that the issue must be either in the obj exporter or else in Blender’s importer, as SketchUp allows faces with interior holes without triangulation.

Is this an option?


Check the options on the obj exporter and see if “triangulate all faces” is checked.

Edit: Nope. Even with it non-checked, exporting a non-triangulated face to obj and importing it back into SketchUp generates triangulation. Looking at the obj file in Meshlab also shows 8 triangulated faces where SketchUp had just one with an inner loop hole.

When you import geometry from most other formats it arrives into SketchUp as ‘triangulated’.

There are ways to strip out these ‘coplanar-edges’ which split faces that otherwise would share the same materials etc…
Thomthom has a ‘cleaning’ extension in EWH…
There are others…

yes this could work with simple cases of n-gons with holes, what is the name of the plugin? :slight_smile:
but i still can’t detect where are thoses possible forgotten ngon in my scenes

no its not about exporting, its just that blender dont support n-gon with holes.

take this case

this is the result in blender

this is what i need to do first in sketchup

just draw some lines do make sure that thoses ngon with holes are destroyed

and this is the result in blender, clean mesh

i just want to have a solution that may help me in my workflow
cotty solution was great for the left ngon with hole, but with ngons with multiples holes i think that its problematic

Hey @Dododododiran did you try Limited Dissolve feature in Blender?

could work on the left model

but on cases with multiple holes inside of the ngon like in the right, or like some buildings with windows, the model is simply impossible to correct inside of blender, adn need to be corrected inside of sketchup before exporting

Hmm, I see, that’s bad. Also note that I tested with glTF and it gave much better results.

Here is a result with glTF (I removed doubles and used Limited Dissolve):

For SketchUp glTF exporter/importer: