The dreaded NGon... Is this acceptable?

Eliket · May 2015

Hi all!

Just wondering, is this acceptable in a 3D model?

I can't remember if I am just recalling poorly, but I think someone once told me that it was a bad idea to have a vert share 5 (or more than 4) faces at once.

Is this true? And if so, what is the reason behind this? Is it to do with performance issues?

An answer would really set my mind at ease.

Cheers guys!

Bek · May 2015

That's not an n-gon (a polygon with greater than 4 sides) exactly, rather called a pole. Whether it's bad or not depends on what the mesh is used for. Will it deform and animate? Then it's probably not great. Is this a sub-d highpoly? if so, how does it smooth? Such geometry isn't inherently 'bad' but there might be situations where a different approach gives better results. It all depends on its usage.

Mad_Minstrel · May 2015

Yep, that's a 5-valent pole, sometimes also called a singularity. You can't actually make any meaningful geometry without poles. Even a simple cube has 8 of them (3-valent).

Eliket · May 2015

Oh man, that makes a whole lot of sense why I couldn't find any examples of this. It is just a low poly model that will be used in a mobile/web game and does not deform.

Eliket · May 2015

Ah thank you too, Mad_Minstrel. That is reassuring! I'll stop trying to move them around/ get rid of them. Thanks a lot guys!

Eric Chadwick · May 2015

Yeah, poles really only matter if you're using subdivision. We have some good tutorials here that explain why:
http://wiki.polycount.com/wiki/Subdivision_Surface_Modeling

WarrenM · May 2015

Poles and n-gons only matter if they affect the end product. It's all situational. If it bakes the normal map fine or animates in the way you want, they don't matter.

The dreaded NGon... Is this acceptable?

Replies