Importing fitted mesh turns clothing into a black hole

[Inilth]

I've been following along with a few tutorials and the only difference I'm seeing is that the avatar I'm working on has far more bones and for whatever reason I'm unable to bend them? It just sort of grabs a section of the body and goes off with it instead of allowing posing.

 

My shirt is just a tiny vest thing to learn Blender. It's rigged to where its at but it looks like this, trapped inside the body: https://imgur.com/a/5USzfiT

Also included is the bones and what happens when I try to pose it. I haven't been able to find a tutorial that matches a body like this.

Dummy:https://www.dropbox.com/s/09qavxgtz0l26zy/SnokraSnake_Dummy_v0.91.rar?dl=0

 

I'm assuming it has something to do with the rigging. Why doesn't this body bend like the others? Thanks.

[OptimoMaximo]

From the looks of things in your screenshot, that is an Avastar rig. I'm quite confident that the bones you can't bend are the blue ones, because they're constrained to (invisible) green ones.

The blue bones are those you should weight bones influences to, while the green ones are supposed to handle animation only and shouldn't be in the vertex groups list at all.

Moreover, you're using collision volume bones there, to get a fitted mesh result (red bones). Those bones are being handled by the Avastar add-on scripts, as Blender can't manage bind poses, natively. This is indeed what squeezes your mesh inside your avatar once imported.

Solution 1: purchase Avastar and use its tools and exporter to get rid of the collision volume bones problem and keep going with your learning

Solution 2: remove the collision volume and the animation bones, rig only to the blue bones. Make sure to orient the character facing the +X direction and apply rotation on both mesh and skeleton before exporting

 

[Inilth]

Thank you for clarifying! I had been wondering if it was due to me not using Avastar. I  may go ahead and purchase it.

Edited March 23, 2019 by Inilth

[Kyrah Abattoir]

Could be a scaling issue? It's common practice to make sure that there is no funky scaling in a mesh before exporting it. You can apply scaling in the "object" menu.