Rigging Issue Around The Crotch

[Spibe]

Hello, I just modeled a pair of jeans, and made the textures.  Now I've gotten to rigging.  I'm not very good at it, and don't know much about it.  I use 3ds Max for modeling, which is what I'm proficient in, but I rig in blender (which I'm not very familiar with) because there's a copy bone weight tool that makes rigging a lot easier.  It works really well, like the rigging is flawless except around the tricky areas around the crotch when you sit down.  The rig looks fine except when sitting down.

I read somewhere that topology might be the issue with it.  But I was hoping to get some input to see what I could do to fix this.  Also... seeing as you need to make all the different sizes for standard sizing.  Do you have to rig each size seperately or can you resize them after they are rigged?

And if it does happen to be topology that's the issue.  Is there a way to fix it without messing up the uv map?

Here is the issue that I'm talking about:

 

[hibit Spad]

Spibe

 

Are you modeling the inside of the jeans as well as the outside?

 

If so, I really reccomend you delete the inside mesh.  No one will see the inside and your rigging wil be easier.

 

 

[Leviathan Flux]

I am not sure how rigging goes in blender, but looks like you need to smooth the weights across the crotch area so that some of the hips influence the other opposite one and overlap.   So for the left hip, for example, you should have a bit of influence across the center axis of the AV onto the upper part of the right hip, but just enough to not get this kind of effect.  Try rotating your joints as you do weights to test it. 

Topology is also important, but shouldnt cause this kind of problem here unless you dont have enough divisions or if you have faces on the inside as well that are poking through that dont need to be there.  

Also, no you dont need to rig each separately.  I use Maya, and at least there you can bring the other sizes in and copy the weights to each one from the model you do weights on.  Depending on how different each is from the others, you may  need to polish them up but shouldnt be much work. 

[Spibe]

No, I only have the edges have a little bit of folds on the inside so that the invisible faces won't stand out so much.  There aren't double faces around that area though.

[Spibe]

Good to know thanks.  I was worried that I'd have to rig a bunch of times.  I'll probably have to custom-rig in max, even though the last time I tried it went horribly.  I know there is a way to copy them to each one within 3ds Max as well, but I wasn't sure if resizing it would mean you had to re-rig it.  I  guess my only solution would be to custom rig it.  I'll post what the mess of my topology looks like.  I don't even know how it got so crazy @_@  But do you think this is still riggable?

 

 

And here's it zoomed out for a better view: