View Full Version : smooth Binding Question

02 February 2009, 06:08 PM
so i've finally gotten through my training dvd's for character rigging which i've been watching for the past month to get pieces of info here and there for a complete rig for my baboons, and i've got one thing i can't figure out because it was done differently on the 2 dvd's:

the very tip skeleton joints on the end of fingers, toes, the head, the circular end on my skeleton that lays just outside the edge of the model surface - INClude or EXlude the tips for the bind?
That would be the difference between using "selected joints" and "joint heirarchy" for the bind.

and i did figure out what was wrong with my paints weights modeling, but apparently, painting subD model requires a lot more going over than poly's.

02 February 2009, 06:23 PM
I would go with INclude. I would also scale in or move that last joint to be right on the edge of the model, or even maybe a little inside the model instead of being completely outside of it.

Doing so will allow those joints to hold he geometry in place at the ends of your model. For example, I doubt you would want the top of your baboon's skull moving with other joints in the head. The skull, or top of the head, doesn't move, the skin may, but the skin itself doesn't. Allowing end joints to have influence on the model will allow you to weight the top of the head to that joint. Same for the other joints and part of the model as well.

Anyone feel free to correct me if I am wrong here, that is just how I would go about it myself.

02 February 2009, 01:39 AM
Only exclude the tips if you built the rig with an extra joint in each case where the chain terminates. That would mean in the fingers you went MidA, MidB, MidC then MidTip. That Tip joint is extra and will not be animated. Every vert at the tip of the finger should be bound to MidC and not MidTip. That is why it has a option to exclude this extra last joint at the end of every chain. If you are unsure of this then do not exclude that joint. Leave it in and then just give it no influence in weight painting.

You tend to find that you make this tip joint alot but it serves no purpose in most cases. It looks nice and makes your skeleton look like it has tips to the fingers and not the top knuckle cut off. In film no one cares how many joints it takes. In games every joint is preacious and you don't waste them.

I like to bind based on selected joints so I know what has influence and what does not but binding to the hierarchy has its advantages as well. Most of them deal with transfering weights from one character to another on the same rig type.

My advice just bind to the hierachy and leave the tips in.

02 February 2009, 02:14 AM
Wouldn't a "plus" to having tip joints be that the joint behind it is automatically oriented correctly, since the joint has an object to point to?

02 February 2009, 08:02 AM
thank you all very much for getting back to this post! i was originally wondering why the last one would be left out if it could be tucked just inside or on the skin surface and not be used, but since one of the 2 training dvds, this one with a reputable TD said it don't use them, and i'm not doing his job and he is, i thought i should ask.
the other TD's model has the tips outside the skin, but did include the complete skeleton in the bind, and for the record, he was also using IK's [2 on each leg]. I think i'll try first to use the tips outside the surface and use selected joints to see if that works better for the painting weights process, see if it makes any difference while moving stuff around since i'll have to be rotating joints around those pieces initially while painting on subD, which is a harder surface to weight paint, atleast on my computer.
if selected joints is a problem, i'll switch to complete hierarchy. I'm trying to use this model for an animal character that's both biped and quadriped [thus the 2 IKs]. and the rig will be visually based because personally i think best in pictures and numbers when animating. [werdz, bad.]
i've corrected all of the local axis, including the tips, including the ones tuck outside the surface.
and i will post the rig job as soon as i'm done. thanks again.

02 February 2009, 01:36 PM
I wouldn't bind the tips.

And here's my reasoning. First of all binding to all the tip joints has no effect on the way the skinning looks. In a finger a joint influences everything below it, so if you have a joint from the last knuckle to the tip, you need only skin to that initial joint. It doesn't retain the shape for the tip of the finger any more than the initial joint why include it?

It also creates extra data for the extra influence is an extra thing Maya has to evaluate. We want to reduce redundant data so that the rig is as light as possible.

02 February 2009, 03:18 PM
In Maya, the tip joints are just there for reference and usually don't affect the mesh at all. As D-brooks said, you are doing yourself a favor by excluding them from your rig because it will help the computer evaluate a little better.

Having said that, you're probably not assigning any weight to those tip joints, so you probably won't notice any difference in framerate regardless of what you do (unless you're duplicating this rig over and over again in your scene). It is still important to form good habits, so I still suggest excluding them but it's not the end of the world if you've already bound the skin and don't want to go back and re-bind.

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