Bones shrinking ANY mesh!

[Ryan Davanzo]

I'm trying to fix this for 2 weeks but nothing changes! I can't paint nothing with the weight paint tool and move the bone or it will shrink! People say it's because it's connected to more armatures or 2 bones painted at the same time but...it isn't! I created an new project and placed one single armature and bone on the default cube and when I rotate it, the cube shrinks, so maybe I messed up some configuration? Sorry for bad english if any :v

[Pte Jack]

A gif or video showing the problem and your entire workspace would help.

[Ryan Davanzo]

https://imgur.com/XQSacza

I somehow managed to fix the torso, but not the rest ;w;
And I can't remember what I did exactaly

[Pte Jack]

It's hard to see there, do you have 2 bones in the wrist, but your weight painting looks like you're painting that mesh to be activated by a twist bone and it is offset weirdly. For arms the weight should be less at the joint above getting stronger to the lower bone. That mid upper arm bone shouldn't have weight up into the shoulder bone.

Maybe watch some of the weight painting videos by this guy. They move quickly, so you have to pay attention.

https://www.youtube.com/watch?v=rG82fogtuCg

[Ryan Davanzo]

I recicled almost the whole body and skeleton from garry's mod, so the bones have their original weigh paint...unless it was because I added more bones (ears, hair, etc), but I'll check the vídeo :3

[Ryan Davanzo]

Yeah...it kinda helped a little but I still have the bug! ...I think I'll reset Blender to the default configs and re-do the entire thing again.

[Pte Jack]

Bones don't have weight painting, Mesh is weight painted using vertex groups to the bones of the same name as a vertex group.

When you say you recycled "almost" the whole body of a GMod model, what does that mean? Did you repaint any of the mesh in the arm and wrist? Did you delete mesh from that area and replace it?

As I said before, it looks like the bones you selected in the GIF you provided are twist bones. Certain areas of the mesh are painted to those bones in order to allow you to adjust crinkling caused by posing the main bones. The wrist action looks correct for a twist bone, but that other one near the muscles between the shoulder and elbow bones, the weight painting for that one is totally out to lunch.

[Ryan Davanzo]

The only thing I did was add new bones (ears and etc as said before) and paint the new head! Nothing else!

[Ryan Davanzo]

And now the mirror tool wont work for my other model...

[Ryan Davanzo]

I can't fix it ;-;