View Full Version : Skinning techineques
07 July 2007, 07:09 PM
somebody help me in skinning characters, techinequs to makit fast , and the rules to be maintained like the (volume ) and so on
07 July 2007, 11:05 PM
Well I feel that the initial start is crucial meaning that if ur character is suppose to be symetrical, make sure the geometry as well as the skeleton is prefectly symetrical. This will be huge later on when you decide to mirror the weights.
There are many ways to go about skinning a character. The first rule and number one rule is to lock all influences. This will ensure that you dont edit influences that you intended not to. I like to only work on 2 to 3 influnces at a time. Creating an animation so that you can scrub the time line while ur painting weights. It really helps you see ur progress and how the geo is deforming. To fine tune the deformation, use the component editor.
07 July 2007, 05:25 AM
Check out Ian Jone's "overweighting" skinning tutorial. Helped me out a ton:
Also, if you are using maya 8.5, there is the special little trick I use to speed up initial skinning with dense meshes. You create a very low proxy mesh that matches the proportions of your high rez mesh and skin that. Because maya 8.5 has the ability to copy weights based off of "closest point on surface" method, you can then bind your high rez mesh to the same skeleton, select the skinned proxy mesh, shift-select the high-rez, and goto Edit Smooth Skin>Copy Skin Weights.
08 August 2007, 06:33 PM
Yeah Maya 8.5 has some great tools for copying wieghts and UV's from one mesh to another. Brilliant stuff. But you can still do this in earlier versions, the tools just aren't as robust.
The basics. Joint placement is the foundation to basic weighting. Experiement with it. Do test binds on a paticular joint and see where its best place will be. If your joints are well placed... the weighting will be much easier. A quick guide to joint placement is first go to the center of the mass and experiement from there. At this point you should always be thinking pivot point, Where is this mass pivoting from? Because of how skinning algorythms work, you have to do allot of faking to get the masses working right. So try to think of it like the computer thinks of it. Get even predictable results so when you go in and throw more custom deformers on top of it you will have an even predictable base to start from.
Painting weights. I prefer to work from the areas with the most complex interactions to the areas with the most simplistic interaction and then make liberal use of locking skin weights to protect the areas I have weighted. For example I will usually weight the clavical shoulder region befor I weight the torso. That way I don't weight the torso all nicely, then have to go back in and reweight regions of the torso once I do torso/shoulder/clavical/scapula interactions. I'll also weight the jaw before I weight the head and neck or the palm/knuckles before I weight anything else on the hand. While painting weights, pre-animate the joints you are weighting. this way all you have to do is scrub in the timeline to check your weighting. Always have your wire frame showing. How your wires move will tell you how your textures will move. If it looks good with wires, it will probably work well with textures (and avoid texture stretching issues). Then test it with a quick render using a grid pattern just to be sure. While painting weights, if you use any function other than add it is a good habit to lock all the other influences you do not want to get any weighting. Features like smooth weights work really well, but can redistribute weights unpredictably when you are not careful with it. I made a little mel script that will lock/unlock all the joints on a selected mesh to speed things up for me.
I also prefer to rig before I paint the weights. It speeds up weight painting when you know exactly what you are painting the weights for. For example what combinations of joints will be moving to make the poses the character will be getting into.
08 August 2007, 12:35 AM
Nice post, twedzel.
I would suggest that when you animate the joints, that you animate several of them at once instead of one bend at a time. In my rigging class, it has burned people many times when they think they've got an area "normalized", then they rotate a neighbouring joint close by only to reveal that some influence got spread too far. A good sign of this is to look closely at your gradients when painting. If an area is deforming correctly, but the gradients look fragmented, something is wrong. Trust the greyscale over what you see sometimes. I like to think of weights like dumb sheep, and you are the herder. They don't know where to go, so you've got to coral them in one spot first and slowly distrubute them to their proper places while keeping the herd together, working down the heirarchy.
I also agree with rigging first. In fact, I try and keep the rig skeleton and the bind skeleton seperate entities. I almost never constrain or IK bind joints directly. This gives me flexibility in the bind skeleton and allows me to use multiple versions of a rig, like, if I'm taking it into MotionBuilder.
One other thing I'll mention is to make sure you are thinking of "bone" influence and not "joint" influence. It sometimes throws people off because they think that the area of influence for a joint is a "radius" around the joint.
08 August 2007, 02:38 AM
I would suggest that when you animate the joints, that you animate several of them at once instead of one bend at a time. In my rigging class, it has burned people many times when they think they've got an area "normalized", then they rotate a neighbouring joint close by only to reveal that some influence got spread too far.
Which is another reason why I like to rig before I bind.
08 August 2007, 02:38 AM
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