I really need some help.

So there is this 3D model I’m making, and I’m trying to add bones so that it’s easier to animate. I don’t understand why this is happening:

That part of the model just bends and turns, and I don’t know what to do.

you should just parent the parts to bone in strg+p menu, not with automatic weight. Choose part then choose armature, go posemode, select bone and push strg+p. And maybe apply some transforms strg+a and mirror modifiers before parenting to the bone and check the boneroll strg+n or properties, they get always flipped on mirroring.

Moved from “General Forums > Blender and CG Discussions” to “Support > Animation and Rigging”

It looks like you have multiple manifold meshes, part of a single object, and you are trying to weight them to an armature using automatic weights?

Automatic weighting doesn’t know what it should weigh the hands and fingers to, because there is no bone reachable from inside their volumes.

You could do what donnydarko says (“strg” probably means “ctrl”, I had to look that up).

You could also assign the hands to the forearm’s vertex group, or create hand and finger bones that lay inside of the appropriate volumes and then regenerate automatic weights.

This rigging tutorial shows you how to assign vertex groups without automatic weighting: