Painting Skin Weights problem, jittery

[cyriacksdamon]

I've repainted the weights several times now and just dont know what I'm doing wrong  ...

They should be smoothley painted, like this:

but when I move the rig's leg, it ends up weird and distorted like this:

It gets worse the further I move it... does anyone have any idea what's going on, WHY it's going on, or how I can fix this?? 

Thanks in advance. I'm using Maya 2014.

[Cagetron]

Try selecting the vertices that look wrong to you.  Go to Window > General Editors > Component Editor, then go to the Smooth Skins tab.  Look at what joints are have weight for those vertices to try and figure out which joint(s) seem like they should not be influencing those verts and correct them.  In the Component Editor you can also go to Options > Hide Zero Columns to help you look at it.  

An additional approach you can take is just set your paintbrush to Add, with Opacity and Value set to 1.  Then block out your weights for each joint like this.  Then get into making them smoother.  It may help you to initially not have your influences spread out too much with joints influencing verts they shouldn't be.  

Also, make sure your weights are normalized.  Skin > Edit Smooth Skin > Normalize Weights.  This means all of a verts influence weights add up to 1.  In the paint skin weights tool Normalize Weights should be set to Interactive.