Skin issue - Mechanichal Rig in Maya

Psyminator

Hi everyone!
I'm having problems with skinning geometry to joint chains, that is attached to another joint. The IK works fine by its own when I'm moving it. From image #1. In image #2 I'm moving the IK by my self and the skin-function seem to go just as it should. But the IK cannot be moved as a parent to another joint chain. Unless the rubber hose "flies" away on its own. I've watch some video on YouTube with the same problem. But they cannot figure out what's wrong...

Any idea how to fix this problem?
Appreciate any advice!


Look carefully how the rubber hoses below, on the base of the excavator arm bends toward the motion just fine. The rig only fails once the joint chain is connected to another joint chain. It seems...

kwyjibo

This works.

Joint chain for hose (green) should be child of digger upper arm (red). IK handle(yellow) for hose chain should be child for digger lower arm (blue).

Psyminator

Hi kwyjibo!
Thanks for answering!
I show you with this picture exactly how I've done. As far as I can see my chain of joints works basically the same. The red joint on your picture is the same as EC750E_boom_joint and the blue one is EC750E_arm_joint. Both IK's are parent to the arm (blue) and the rubber hoses is parent to the the boom (red).

Think I'll try to make an easier example next time before something complex as this. Still, this seems really weird.

Psyminator

Maya always creates these brown extra joints to support the other hose joint-chains... for some reason? I'm suspecting this is a problem with the translations when I'm skinning the geometry to the joints, rather than the exact hierarchy?

kwyjibo

Most likely it is double deformation caused by having your hose meshes parented to a moving/rotating/scaling transform.  Ie. the vertices of the mesh are being transformed twice, once by inheriting its parent's transform, and again via the bones they are skinned to. Are your hose meshes parented to joints in your skeleton hierarchy? All Skinned meshes should be placed outside of the joint hierarchy. 

Psyminator

Oh, that actually worked!
I took it for grandet the hose mesh was supposed to be parented with associatied joint group.

Thanks for the help mate!