Why do game devopers use triangles for their models, when they could easily cut the number of polys in half by using quads?
A quad is just 2 triangles so You save nothing. As long You not using subdivision triangles works well.
Most game engines would convert the resulting quad mesh to triangles anyway.
Quad polys can also be particular, sometimes the face is rendered as concave when you want it to be convex, solution? tris…
There is a balance, tri’s aren’t like a disease, it’s just that people can get carried away with them, and quads make topolgy look… nicer - usually…
(And quads are potentially horrific in physics bounds…)
Basically, quads are easier for people to understand, but tris are actually what the computer deals with. It’s like how we do math in base 10, but it gets converted to binary for the computer; we do modelling in quads, but it gets converted to tris for the computer. Also, tons of developers use quads and let the computer do the conversion to tris, but that always leaves the chance for the computer to do it wrong, so it’s best to do it manually, or at least check that the edges are all aligned the right way.
Example of going wrong:
I modeled a landscape for a vehicle. I just subdivided (multi fractal) a plane. That was good enough.
BUT:
I drove the vehicle over the landscape but the vehicle from time to time was sinking into the landscape. I was pretty shure I didn’t modelled mud so something else must be wrong.
A:
because of the randomnes the “quads” were distorted and not flat anymore.
B:
- the render engine converted the quads to two tries
- the physics engine converted the quads to two tries
but both engines split the quad at different diagonal.
The result:
- at diagonal the vehicle drove through a valey, while the landscape was shown as a hill ;).
Solution: Converting to the landscape to tris before running the BGE forcesd both engines to use the same face layout. And yes it looks ugly in Blender :P.
Conclusion: What is good at design time, is not necessarily good at runtime.
Monster
Blender mixes quads and tris, it doesn’t bother converting them. Bullet, however, might. If you don’t have freaky, non-planar quads, this shouldn’t be a problem. I could see randomness introducing non-planar polygons to your mesh though…
@Monster - I noticed that awhile back with my game, where the Player wouldn’t exactly be above the ground. It’s nice to know why that exists, and that it’s fairly simple to fix. Thanks for the information.
@Moguri - Thanks to you, too, Moguri. Nice to know that Bullet is the one that converts the mesh.