Use of N-Gons in 3D models?

[Beale]

Being the very definition of amateur in 3D modelling, I've only just learned of N-Gons. Apparently they are bad.

But, my question is "how bad?". Obviously little information online is not related to KSP, and quite vague.

So, can anyone inform me if these types of faces should really be avoided?

Example: I've been using N-Gons forever - this Soyuz interior, the control panel face is a very-high-gon.

In a nutshell.

Or

[Whirligig Girl]

So why are quads better though?

[Van Disaster]

Everything is made of triangles in the end, keep that in mind - even quads are bad if you bend them & don't pay attention to the triangles they're made up of. I've honestly forgotten most of the reasons ( although it'd be easy to look up ), Max's mesh smoothing mods - and I presume everything else's - don't really appreciate them too well though, and you can run into issues with smoothing in general if you're not careful. If it's a flat surface then make it out of whatever the hell you want, providing it's always going to be flat ( ie you're not animating it ). Possibly might get some artifacts from a LODding algorithm. If it's curved try and stick with quads at least, it'll be safest for exporting.

[maccollo]

Like Van Disaster said, as long as the Ngon is flat, and the edges around it are hard, and it's never animated then it's fine.

The issue with N-gons is that when they are triangulated this will happen in a completely random matter, so if you aren't careful you can get some really ugly results. If your N-gon has any concave elements it might even cause overlapping faces.

So why are quads better though?

Quads are considered to be better because they allow you to have non-extraordinary vertices, and when you subdivide a mesh with extraordinary vertices the mesh will either pinch or pull away from them. Other than that mesh editing tools work better with quads, and they actually make the mesh flow readable.

Edited March 28, 2015 by maccollo

[landeTLS]

For lowpoly flat areas ngons are a-ok(edgesplit or seperate smoothgroup). The only issue with them is that you cant predict exactly how they will be triangulated once ingame. That might not be a problem for you as they will "always" be triangulated to the lowest amount of tris. But if its important for you that they are a bit more even then you may want to do the triangulation manually For consistency.

But basically anything that will be smoothed(eather by smooth shading interpolation or subdivision) will look wierd with ngons.

if you are subdividing your lowpoly or making a proper hipoly from it to get better ao baking etc you will want to atleast inset a support loop around the ngon.

For both your examples ngons are ok as it will not create any visual differences.

i only worry about quads if i want the mesh to be kept easily editable, animated or if im making a hipoly Model.

Edited March 28, 2015 by landeTLS