Friday, August 27, 2010

The importance of Geometry Flow

As the schedule goes, right now I ought to be rigging the chef character. I'm a couple days behind schedule, but for a very good reason relating to bone-based (or joint-based) face rigs. The next post will likely cover that.

For this post I'd like to go a couple weeks back in time and show you two images of the chef as I was working on him:

I'd like you to look at the areas around his shoulder. When I was first modeling the character, my first temptation was to just take a chunk of his shoulder and extrude it straight out. That would make sense, right? Just drag out some part of his chest like a piece of play-dough and BAM! Instant arm.

The problem is that when this gets animated, this first approach fails miserably. Characters spend their time with arms down at their sides in one manner or another, so this first character's shoulders would be stretched into ugliness for a huge majority of the time.

After some sound advice from my good friend/mentor Christine, I took a much closer look at how professional characters were modeled for various game engines. Most of the geometry on these characters was modeled to roughly follow the nearby muscle groups of the character. For example, even on characters that were fully clothed, you can still make out collections of shapes that flow in the same way that pectoral muscles flow. It just makes for nicer deformations while the character moves about.

So in the end, I decided to completely rebuild his upper torso. It took a bit of reworking, but now the geometry drapes across his shoulders almost like a tunic. Now as his arms drop to their sides, the geometry of the shoulder deforms in a more natural way. And I'm pretty darned pleased with the result!

From this experience, I have adopted a rule of thumb to always try to keep large muscle groups in mind while modeling. It's not an exact rule, but it helps to avoid the pitfalls of some possibly terrible deformation down the road.

1 comment:

  1. That makes sense! It seems like a good philosophy to keep in mind when animating clothes traditionally, as well... humbug.