View Full Version : Is triangulation necessary for game models?

02 February 2003, 07:12 AM
Do game models have to be triangulated in order to work in a graphics engine?

I notice that when models are triangulated the poly count increases a lot which sucks if it's required.

02 February 2003, 08:49 AM
well, quadrangles are really just two triangles. so if you have a model in quads that you think is 600 poly's, you're fooling yourself; it's actually 1,200.

sorry to break it to ya! lol

oh, and i'm not aware of any game engine that draws more than 3-sided poly's, except for this one that i heard uses NURBS. oh well, whatever...

02 February 2003, 11:46 AM
Is it just me or are people increasing getting confused about what a polygon is?? 3 vertices connect to make 1 Polygon (tri) not real hard.
Probalby stems from more people using Poly modelling instead of editable mesh modelling in MAX etc. and the fact that max renamed poygons tris and Quads polygons lol

02 February 2003, 01:01 PM
So it's okay for me to leave my model with quads?

02 February 2003, 01:44 PM
What do you mean with 'ok'? It's ok if you want to work on your model since the polyobject enables a bit more flexibilty but when you publish your work, not changing back to editable mesh is cheating.

Snowfly - even nurbs are triangulated at some stage to render them out. The only advantage of using nurbs in a game is that you can do seamless LOD.

02 February 2003, 08:20 PM
caustic, it confuses some people because a polygon is a flat, closed, geometric figure with only straight sides. that's the actual definition of a polygon. so all triangles = polygons, but not a polygons = far as I understand, triangles are the simplest polygon, so that's why games use them.

02 February 2003, 08:35 PM
Yaeh, a quad is also a polygon if his four vertices are contained in the same plane ... more or less there are polygons of three, four, five and all wath you want if all the vertices are in one plane.

02 February 2003, 12:51 AM
solve: it would work, but i really don't recommend it. traingulate your model so you can predict what it will actually behave like in game, testing deformations, checking the shading, etc. chances are you'll have to turn a few edges, maybe even collapse some wasted geometry.

definitely keep a quad version handy though, in case you wanna go back and edit some more. ..btw what game was it you said you were modeling for? :D

krystman: of course. i was thinking more along the lines of exporting your NURBS model as a NURBS model and not a polygon mesh. thanks for clearing that up anyway.

02 February 2003, 04:46 AM
im not getting exactly what triangulation is.. Is it going around and cutting all quads in two pieces?

02 February 2003, 04:56 AM
All 3d realtime geometry is triangles, so yes you must triangulate your mesh. Either you will do it or an exporter will do it but it's going to be triangles when it gets in game. It's much better to do it yourself for the reasons Snowfly mentioned.

The way you triangulate a Mesh in Max is convert to editable mesh. To show all the hidden edges go to edge mode, ctrl+a, scroll down and click on "visible".

02 February 2003, 06:20 AM
Burrowingduck / jpastor: I understand that you can have more than 3 vertices to make a polygon, but the smallest polygon is a 3 sided one and thats what people need to count to get a true poly count for games development.
I could have a million vertices on a flat plane and call it a polygon but Im pretty sure it wouldnt be efficient. :P
Seems to me people are getting stuck when using quads and assessing their true triangle polycount, which to me has been a pretty recent development and one that is growing amongst newer modellers.

02 February 2003, 01:57 PM
caustic: Yes, AFAIK Direct3D only draw triangles because a shape defined with three points is always a polygol. Other programming API like OpenGL allow quad and more complex polygons but advice you of it because if all the vertex aren't in the same plane (not a poly) the representation can be unexpected and some calculations can be erroneus (ie: lighting, textures, ...).

CGTalk Moderation
01 January 2006, 12:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.