View Full Version : polygons vs. triangles

05-07-2002, 02:36 AM
hey everyone!

i got a really simple question that is kinda confusing me.

what's the difference between polygon and triangle counts?

thanks. T

05-07-2002, 03:46 AM
Triangles are polygons, but polygons aren't necessarily triangles. All polygons that have more than 3 sides can be broken down into triangles. The polygon count is the total number of all polygons ( including triangles ), while for the triangle count, the polygons are broken down into triangles, so it's not longer a mix of n-sided polygons and triangles, it's all triangles. For instance, say there is 1 quad, and 1 triangle in a scene. The poly count would be 2, but the triangle count would be 3 because a quad is broken down into 2 triangles.

05-07-2002, 09:49 PM
@@Triangles are polygons, but polygons aren't necessarily triangles.@@

Wrong! Polygons are always triangles. Just because the application shows you a n-sided polygon it doesnīt mean it isnīt a triangle. ;) Normally n-sided polygons do not exist. You can see it as a fake. Programmers should know it! :) This is a shake-down!!! :))

Every Polygon that is "not" a triangle are several triangles.


05-07-2002, 11:21 PM
First, I was talking about polygons in a geometrical sense, which certainly do exist you goofball. :p I am a programmer as a matter of fact, and I know that polygons are triangulated before they are rendered, but that doesn't mean n-sided polygons aren't really there, as far as the storage of the geometry in the file goes, there are n-sided polygons.

05-07-2002, 11:35 PM

@@but that doesn't mean n-sided polygons aren't really there@@

Oh yes, thatīs exactly what it means! :p

@@as far as the storage of the geometry in the file goes, there are n-sided polygons.@@

Thatīs partly correct, but the storage of the geometry in the file is just a reference for the programm. The real code is of course converted by the app internally. And the app does not know any n-sided polys at all! Conclusion: n-sided polygons do not exist! :applause:

But I guess thatīs not the kind of answer phantomgti2 wanted to have! :p

Of Course I know what you wanted to say! :)


05-07-2002, 11:55 PM
"And the app does not know any n-sided polys at all!" Here you are wrong. Programs do some operations on n-sided polygons, it does not necessarily triangulate for everything. Triangulation is only good for certain operations. Don't make me bust out my graphics programming books. :)

05-08-2002, 12:07 AM
Best answer to the question:

Triangles are just that -- 3-sided faces. Polygons can have 3 or more faces. Some applications which distinguish between triangle-based geometry and polygonal geometry will report polygon count differently between these two object types. 3dsmax, for instance, will always report the number of triangles on an Editable Mesh object even when it appears in the viewports to have faces with greater than 3 sides. But for an Editable Poly object, Max will report the number of true polygons.

The difference may only be one of semantics, but it becomes important if you're making models for a game, since game engines triangulate everything. If you're working with n-sided faces in your modeling package, you'll still need to keep the triangle count in mind so that you don't exceed your geometry budgets for the target application.

05-08-2002, 12:16 AM
phantomgti2 skip all the other replies and just read LFShade's, it's much clearer.

05-08-2002, 12:23 AM
graphics books? Got three of them always besides me! :)
But I agree, just read the answer of LFShade. :wavey:
We are just talking ****! :scream:


05-08-2002, 12:58 AM
Oh yeah, forgot to mention. Here's a rule of thumb for the triangulation of polys with greater than 3 sides:

A polygon with n sides will break down into n-2 triangles.

05-08-2002, 03:18 AM
thanks guys for all your input.

05-08-2002, 06:36 PM
Originally posted by LFShade

Triangles are just that -- 3-sided faces. Polygons can have 3 or more faces.

I believe you mean Polygons can have 3 or more sides.

05-08-2002, 10:17 PM
Thanks. I really need to read over my scribblings before I post them:thumbsup:

05-09-2002, 05:35 AM
HA HA HA LOL. Yeah I have to be careful too.


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