NGON i dont get it

what is the big deal about N-GON’s

is it bad to not use N-GON’s ?
is it good to use N-GON’s ?
dose polygon count will be less in N-GON’s ?
will it effect blender to use less calculation and be faster ?

when blender has no N-GON’s i could keep a mesh clean with loop cut etc…

can some one please help me understand what is the big deal about N-GON’s ?

thanks allot .
i just want to understand

The only polygons (n-gons) supported by Blender are Triangles and Quads.

Although you can model with just vertices and edges, typically if you want to see objects in your render, you must use faces (polygons).

If a model is created using only quads, it will have half as many faces as the same model which uses only triangles. Half as many faces can mean faster renders (although not twice as fast).

i am asking cause blender 2.5 going the support N-GON’S
and all other 3d application support them
personally ,i got use to the idea of modeling in faces and i like it
may be i am missing something
what are the advantages and disadvantages?

A polygon with more than four vertices actually is harder to process. Even a quad requires special processing. Only a triangle can be trivially processed by a rendering engine. To that end, Blender uses OpenGL and the newer versions of GL are phasing out any polygon that is not a triangle. This isn’t a big deal now, but it means that in the future, Blender will no longer be able to pass quads to GL to be rendered. It will have to triangulate all polygons with more than three vertices and it will have to do so in software (slow).

Actually, come to think of it, I’d be surprised if Blender is passing quads right now. I’m pretty sure they are being triangulated prior to rendering.

Yes, not a “speed” advantage in any processing way…

and it will have to do so in software (slow).

Shouldn’t really make any noticable difference as the mesh would only need to be tesselated to triangles as a pre-process and then just the once… maybe it’ll add a few milliseconds on starting the game engine…

So why then are they so popular?
… they are a big workflow enhancer and can make changing topology or adding features into your mesh much much easier, especially for fans of “box modelling” where you “cut in” and subdivide your geometry to progressively refine it to what you want…

thanks for your answers

ok i think i got it (rendering) :slight_smile:
so pre rendering will take more time . so this is not so bad i think
(hope i understand right ?)
the question is what is better. 4 quad faces , or one N-GONE with 8 vertices ?


what about modeling or editing
i notice when i am editing with allot of faces blender (2.49) become very slow , and freezing some time
lets say same blend file (without changing to N-GON) will be faster to edit in blender 2.5?
will N-GON’s make editing faster ?


what about mesh topology , dose using only 4 vertics faces will make the topology more clean ?

thanks allot

It depends on what you rmodelling.
They can help in the workflow, like Micheal mentioned.
I’ve seen it recommended to keep them and triangles out of the final product, cause they cause pinching when subsurfed.
But some people also use them regardless, once you have more experience modelling you’ll learn when you can break the rules for your own projects.
I don’t see how N-Gons would make blender run any faster when in edit mode, thats just how it is, with lots of faces, a complex scene, its bound to slow down.
I believe its RAM that solves this.
But thats what layers are used for as well.

And topoolgy wise, quads is considered clean, but like I said, their are models that use triangles and N-Gons.

well ,
so its not really matter just make modeling more easy ?

and how is box modeling comes into play with N-GON?

sorry i have to much question , this was at my back of my head for some time

Ngon’s are multi sided faces, so when you cut a four sided face, the faces around it don’t need to be triangulated. Then you can go and clean up the Ngon later, without having a nasty mesh of confusing triangles. It’s way easier to make adjustments and things like that. You should check out some BMesh videos to see what all the fuss is about =)

Ngons really aren’t as spectacular as some people make them sound. You’ve simply got a couple of triangles that pretend they’re on big face, which means you can lay the edges between the vertices without having to delete it all and placing entirely new faces. Considering the current way that BMesh connects vertices is selecting two and then pressing Y, I doubt it’ll be much of a workflow speedup at all.

Ya, NGons are just a modelling and storage convenience. When modelling in wire mode, your mesh looks a lot cleaner, that’s pretty much it.

Hardware acceleration, be it OpenGL, DirectX, etc. use trigonometric methods of plane-geometry. Two methods for fast mathematics: a single vertex and a normal defining the plane’s orientation, or declaring a triangle…a plane defined by 3 points, which define both the plane and the face perimeter…makes it easy.

Defining any more than 3 vertices for a face breaks the logic just described since a fourth, or nth vertice need not lie on a single plane. Sometimes you’ll notice in any 3D program that uses FGons/NGons, that there are flaws in the shading. This is because inevitably, the software has to break your NGons into triangles to calculate the shading and rendering. Collision detection also requires plane geometry.

I see it as nothing more than a way to keep your lines in wire-mode from becoming a headache to deal with.

Really, the only thing I can really think of that ngons are good for is making meshes look cleaner, and making boolean operations easier.

thank u all

well i was thinking it was a big dill
cause ,when blender 2.5 say it going to support NGONs, it made a big noise

some more question please :slight_smile:

just to make sure i understand
there is translation to triangles only in render process ?


there is loop cuts in blender 2.5 ?
last time i tried CTRL+R i got nothing.


another simple question , dose one N-GON need to be flat ?
like a quad have to be flat , see blend file for example ?

thanks again all so much


1.blend (123 KB)

Triangulation is always going on; as you can see in your blend, the quad consists of two triangles, there just isn’t an edge drawn between them. Quads and ngons are always made up of triangles, they just pretend they’re not to make editing that bit easier for you.

If all will be well, ngons should work like quads do now. You can see that they’re made up of triangles when you make it not flat, because only triangles will always be flat.

Sorry for my post. I tend to over-think things…

I can say that the build of 2.5 that I’ve tried does not support ngons. Maybe at release though.