Crotch!

This is a tough area to model. It's a place that gets a lot of stress from the legs moving in all directions, and the waist twisting. It's also subject to a ton of shading abnormalities, and nothing looks funnier than a buff and burly space marine with a wicked case of 'camel toe.'

In the illustration below, I'm showing the core geometry layout I go for with every humanoid character I create. In this case, what's being depicted is from the beltline down to where the legs would extrude out from.

When I model this area, I visualize modeling a pair of underwear briefs. Where the legs extrude out from always has a loop of polys in between, seperating the thigh areas. Never have your legs sharing an edge in the crotch- always seperate them with a loop of polys!! So important!

Think about a character running: if there's no loop of polys in the crotch seperating the two legs, when one leg goes forward and the other backward, they're going to be pulling on each other, resulting in horrible deformations and shading. That loop of polys acts as a buffer zone- it wants stress to be put on it, that's what it's for! Not to mention, it's anatomically correct. If there's no loop of polys existing between the legs, the character has no genitals! Yikes!

This is a good piece of core geo to start a character out on. It deforms well, shades well, and is very easy to build upon.

One more note on this crotch layout: I stopped dividing the genitals area directly in half a while ago, as that seemed to lend towards funny shading (camel toe). I always represent this area down the center with horizontal edges rather than vertical ones.