2d Plane with hole causes weird UV map issue (face overlapping lines?)

So here’s one example. The blue of the face is overlapping the line, and when thrown into something like UE4, the texture looks really messed up.

I’m trying to make these flat planes, I’m using the knife tool and then deleting faces off of square planes to make it look like metal sheets with holes/damages The issue is that UV unwrapping these isn’t simple despite it being a flat plane.

This also happens sometimes when I cut holes in a mesh with a boolean, so I need to learn how to fix it. Thanks.

edit: It seems that discovering the problematic faces, dividing them up and then poking them solves it but that is tedious. Looking for a better way, or maybe a better way to achieve my goal and to avoid this entirely?

the point is that here you have two n-gons, and this can bring some issues, the central one in particular is concave and its central point is even external.
To avoid UV and rendering problem you should triangulate or subdivide them : the simplest way is to select two vertices and press J (Connect Vertex Path).

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Hi @Cody38,

It would be better to start with a square ( or rectangle ) that has been pre-triangulated ( sort of like Delaunay triangulation:- https://en.wikipedia.org/wiki/Delaunay_triangulation ).

You can achieve this in Blender by using the sub-division modifier and then a decimate, like so:

It’s then simply a case of deleting faces you don’t need and moving vertices around for the effect you want. the complexity of the surface is entirely down to the iterations of the subdivision and the decimate percentage. This is also a good solution for producing cloth objects as the folds hang more ‘unevenly’, though obviously the resolution would need to be considerably higher.

here’s the Blend file with the above example:
Delaunay_Square.blend (757.4 KB)


Hey that’s a great tip, thank you.