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Smart skin VS Fan bones VS CP weights


Visping

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I am rigging the fingers of a hand and I know of 3 different ways to make the CPs move in a controlled fashion:

Smart skin

Fan bones

CP weights

I have found tutorials for each of them but I have not found the overall explanation how to think when choosing between them.

 

In my case of the fingers, I started weighing the CPs and planned to do some smartskinning in the next step to tweak it more precisely....

But in the middle of the work I asked myself; Is this a good approach?

I am worried that if I combine smartskin and CP weighing it will be confusing, for me, if I afterwards need to correct some unwanted behaviors of the fingers.

What is the best practice?

Is it to keep it clean and only stick to one or does it not matter if I combine them?

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I am rigging the fingers of a hand and I know of 3 different ways to make the CPs move in a controlled fashion:

Smart skin

Fan bones

CP weights

I have found tutorials for each of them but I have not found the overall explanation how to think when choosing between them.

 

In my case of the fingers, I started weighing the CPs and planned to do some smartskinning in the next step to tweak it more precisely....

But in the middle of the work I asked myself; Is this a good approach?

I am worried that if I combine smartskin and CP weighing it will be confusing, for me, if I afterwards need to correct some unwanted behaviors of the fingers.

What is the best practice?

Is it to keep it clean and only stick to one or does it not matter if I combine them?

 

My 2cents on that:

- For very simple movements, CP weights are working well enough. (for instance at fingers it is often enough to use them)

- For complex joints you will like to use fan bones. (especially if you are setting up shoulders, etc.)

- For movements which are not just meant to preserve volume but which will change something in shape (upper arm muscle, a bone which should look out if you move a arm, etc.) you should use smartskins.

 

Often it can be useful to use fanbones and CP weights or SmartSkins and FanBones with eachother.

I find that using CP weights and SmartSkins together can be hard to do in some situations, since they affect eachother too much, but in theory, this can be done too.

 

See you

*Fuchur*

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  • Hash Fellow

I'll add that Smart skinning is something you might add after you've done CP weighting or Fan-boning and still don't quite have what you want.

 

Sometimes Smartskin is easier to do if you already have the joint mostly fixed with CP weighting or Fan-boning.

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  • 11 months later...
  • Hash Fellow

Right now, I'm having issues where wrists are becoming pencil-thin when twisted. I ran across a tut some time ago concerning "thinning" and how to minimize it through different methods, but I'm at a loss to remember where right now.

 

Rich

 

If William's tut doesn't get you going we can look at your case here and figure it out.

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The PROBLEM with 'weight first smartskin later' is that under certain circumstances your weighting will perform perfectly as anticipated, but when you try an altogether different action you might find that a different weighting package is needed. I find that I am constantly re-weighting my characters every time I attempt a different unique action. Smartskin is great but I have found from time to time it tends to 'go away' or gets lost from the file and needs be re-programmed, or as I re-weight it becomes something that needs to be deleted. LATELY- my approach has been to get the character weighted and rigged as economically as possible... animate freely without concern for snapping joints or constricting wrists... and then go about the a 'last pass' of correcting 'issues' via muscle-mode animation in the choreography. I believe I read an article somewhere that explained that Pixar employs a team that does similar corrections.

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Muscle-mode animation is good for fixing cloth simulations, adding jiggle, and other finishing touches :)

I think you have to think of it as one layer building on the other, like a house is built on a foundation...So, if you decide to change the bone assignments and weighting, then of course your smartskins are going to be destroyed. Just like if you decide to remodel the mesh, you will lose textures,weighting,smartskin...One thing builds on top of the last thing...

I try to add fan bones to the hips and shoulders when rigging, to orient like but NOT roll like, to spread the "twist" away from the joint--that seems to be a common joint problem--because though your humerous (upper arm bone) rolls, the flesh at the shoulder doesnt roll as much. So sometimes you could have an intermediate bone for each spline ring coming away from the joint (like at the upper arm) and they all orient exactly like the upper arm bone, but they will each roll at an increasing percentage as they are away from the joint: 0% at the shoulder, 25% next ring, 50% next, 75% last, the next ring is assigned 100% to the upper arm bone.

So that is also weighting the joint (though not at this point using CP weighting)... I have also used ONLY CP weighting, with no fan bones, and let the Mesh pinch when the the bone rolls--then switch to Relationship mode, and add a smartskin reshaping the shoulder at the extreme roll position and at a half-roll position (that creates a pretty smooth smartskin)

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