faces non-planar and non-linear mapping


On some of my models, when i get them from Blender to another application for making it ready for some old engine i am toying with, i usually always run into non-planar faces and non-linear mapping that such other application can detect with just a click (and so easy to fix by converting the selected faces to tris instead of the default quads they were), as for those older game engine, non planar and non linear mapping can lead into some very nasty visual artifact.

But that’s something i would like to do in Blender itself.
When my mesh are very low poly mesh, that’s easy to see those faces with the eye, and so converting them into tris in few seconds, but on more complex mesh there is no way i can check manually every faces to see which ones will lead into the mentionned problem.

How can i do that in Blender, i mean having Blender pointing me to which faces are non-plannar or using non-linear mapping, so i can then easily triangulate them like in other application ?

you can convert all faces to tri’s

just select all and Alt-J i think

is that the problem ?


I don’t think Robsoie wants to convert ALL faces to tris, only the quads where all four points aren’t lying on the same plane. (In a triangle, obviously, all three points are on a plane. Not so with a quad.) So what he’s asking for is something that can identify which quad faces within a mesh don’t have all four vertices on the same plane. I can see why this would be a useful script (not that I could write it, however).

In my mind, you would be able to set a tolerance level (so vertices that are NEARLY on the same plane would be ignored, e.g.); there would be an option to only SELECT the faces that have vertices not on the same plane, and/or it would turn the potentially problematic quad-face into two triangle-faces.

Now that I’ve written this down, it seems likely that this script already exists, somewhere. Anyone?

Yes that’s it, what i would like is to find which of the quads on a whole mesh are nonplanar/using nonlinear mapping, so i can easily triangulate them, i want to keep the other parts of the model in quads.

On complex meshes manually (with the eyes i mean) it is nearly impossible to find in the middle of the lots of faces which ones are non plannar is not productive in term of time, on low poly mesh it is just time consuming but possible.

Other applications less powerfull than Blender, like wings3D are able to automatically select those nonplanar faces, or decade old O2 light that i use for finalisation to get a model BIS engine ready is able to do that too, but i can’t find anything able to do that in Blender

After searching about this problem on google and Blender Artists, it seems like this function does not exist in Blender.
Only closest thing i saw was this thread from last year mentionning some kind of script to list those non planar faces.

But my coding and python ability being null that’s way over my poor old head.
Seems like i will have to continue to use those other applications to solve the non-planar issues after building the meshes in Blender.

i’'v seen a script that shows all the non planar faces

not certain if it’s the given link

i’ll check and see if can find aonther one
but only in 2.49



Thanks for this link, i just tested Frigi script.

It is a bit complicated with those coloring and the fact you need to have 9 materials available is a big problem for complex object that are flirting with the limitation of 16.

So i guess i’ll just use other application along Blender that i hoped to avoid as it is slowing down my modelling process, i wish there was a non-planar selection function like the non-manifold or non-triangle/quad ones that are already in Blender.

send him a message and let him know your problems
ask him if he can make a new version to solve your problems
whci may happen to other peoples too!

may be he can make a new version for 2.53 which would be better who knows!

happy 2.5