Moho Forum

No matter how I monkey around with bones (and I have been, for ages!), I seem unable to eliminate changes of shape when I bend a stick-like arm.

The image here shows what I mean. I have reduced the bone strength to a minimum and the layer is regional binding. Is there a way round this?

How many shapes and how many points do you have? It looks like there is only one point on each side of the joint. Try using three on each side.

Nothing I've read would have led me to think of that - thanks.

I've actually needed to add several points around the joints to minimise distortion. It seems there will always be some by the very nature of the method and the fact that interaction is usually regarded as a good thing.

I'd thought of putting the limbs on separate layers but I imagine that would have been a nightmare to manipulate.

Yeah I get this problem all the time, I wish I knew an easy way to fix it. The method I use I learned somewhere on this forum was to just manually fix/move the points on the vector layer after all my bone animation is set in stone.

Just need to remember to keyframe the vector points just before the arm bends (and starts going wonky) then just after it straightens again (and is back to normal), and then everything in between those keyframes you have to tweak manually.

The problem in this specific case is the lack of points.

Take a long thin cardboard box, bend it in half. This is what is happening when you don't have enough points around a joint. There are only 4 points on each arm section in the example, 2 at then ends and 2 at the joint. When this bends the joint "collapses". Since there are no other points to compensate for the collapse of the joint it "spreads" along the length of the shape to the next set of points at the ends.

Adding points strategically around the joint can help avoid this.

Shoopie, if this is the problem you are having... same thing add more points around the joint. If however you are having the OTHER joint problem where the joint area itself creates a bulge or loop additional bones (called fan bones) can be used with constraints to control those points. There are a couple of joint rigs on the forum that help somewhat with this issue.

-vern