Four sided poly faces

# 1 16-04-2007 , 04:51 AM

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Just got through the cartoon dog tutorial. First, I'd like to say it's a great tutorial, and I learned a lot.

My question... why is it important to try to keep the polygon faces to 4 sides? What's wrong with five side or three sided faces?

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# 2 16-04-2007 , 05:28 AM

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Depending on what you do with 3d modeling, it's best to keep your geometry in quads (4-sided polys) for the sake of deformations. Most game platforms have no issues with triangles. 5+ sides are going to give you outright bizarre deformations when animated.

If it's going to be a perfectly flat surface that is not going to be animated or interacted with (dynamics), you can have 100+ sides for all anyone cares. :p

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# 3 18-04-2007 , 07:56 PM

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I think I now understand what you mean, thanks! How come 3 sided won't matter in games? Won't your objects be moving around, too, like it would in an animation?

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# 4 18-04-2007 , 08:02 PM

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At render time all the faces get converted to tri's anyhow for rendering, if your model has all quads then the conversion is very predictable as it's a case of splitting the quads in half but if you have n-gons (5sided or more) then you have no way of knowing how the n-gons will be split to convet to tris and can give unpredictable results which is another reason to stick to quads even for a still shot.

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# 5 08-05-2007 , 10:15 PM

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thanks

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# 6 08-05-2007 , 10:28 PM

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And to continue where JS left off.

All games render in real time so all models should be triangulated prior to importing into an engine. Triangulation works 100% when models are all quads.

The issue is all about rendering, also its worth noting if you are going to convert your polys into Sub-D or NURBS then n-sided polys will give a lot of issues as will 3 sided. So keep 3 sided to a minimum (only use where there is no other option) and never have n-sided polys.

Chris (formerly R@nSiD)
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