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Old 08-29-2013, 11:31 PM   #1
Basajaun
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Advice for a Character Rig

Hello,

I'm currently rigging a character in 3ds Max for a personal project I'm working on. You can take a look at my progress in this thread. It's the second time I do a rig (I'm not counting another one I did using CAT) and it is proving to be quite challenging. Using Paul Neale's tutorials as my main reference I've been able to complete the rig for the entire body but I have some doubts that I was hoping some experienced rigger would be able to solve. This is the way the rig looks at the moment:



I have, the pelvis, spine, head and limbs done however I'm not sure if this is going to be enough. The thing is that I don't know if the webbing, pouches, belt and holster will deform properly with this setup or whether I should add more specific bones for this area and if so, where should I put them. Here's a picture of the model to clarify a little bit my dilema:



I would appreciate any tips or advice you could offer me. Thanks in advance.
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Old 09-02-2013, 07:26 AM   #2
Zhalktis
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Julius Gerulaitis
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If this rig isn't a game rig, Skin Morph modifier is your friend. Often time it is faster and offers more control than trying to solve deformation problems using bones. Not to mention that it's more straightforward (meaning: probably better for someone starting out), while fixing with bones require a bit of experience of how they behave, or lots of trial-and-error.

If trying to fix it with bones, I'd probably try adding stretchy bones where trapezius muscle is (on both sides) and one stretchy bone between the jaw and sternum (maybe make it squash, not stretch), and stretch/squash bones in place of pectoralis. Also, one twist bone for the upper thigh often helps, especially if the thigh rotates outwards/inwards more often. Maybe a bone for the belly - either with a spring or a control for it, for the jiggles. The model has a digitigrade leg, while the bones for the leg are human-like plantigrade, this means the ankle will probably look fake in motion; chances are you'd probably want to try coming up with something fitting the model more; either having 2-bone IK + the ankle FK from the foot, or a 3-bone IK and then foot.
 
Old 09-02-2013, 07:43 PM   #3
Basajaun
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Thank you very much for your reply Julius. I have taken a look at Skin Morph, checking the documentation and such, and it looks like a great tool, I will definitely be using it. I have a few questions:

- About the stretchy bones: I think I would be able to setup most of them, however I have some doubts about the one from the jaw to the sternum. Would you mind explaining it in more detail please?

- Lower limbs: I made them more human-like to make things a little bit simpler for myself, do you really think I should add that ankle bone?
The twist bone in the thigh is a very good idea, I didn't even think of it.

- For the collar and bottom edge of the shirt, I have created a series of controls using Spline IK. Do you think this is a proper solution or is there a better alternative? Here is a picture to illustrate it:



- Finally, I wanted to ask you about the webbing (the vest-like thing with pouches). What do you think would be the best solution for it? Skin it directly to the existing bones? Use the cloth modifier?

Thanks again for your help.
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Old 09-03-2013, 08:09 AM   #4
Zhalktis
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Julius Gerulaitis
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Quote:
Originally Posted by Basajaun
- About the stretchy bones: I think I would be able to setup most of them, however I have some doubts about the one from the jaw to the sternum. Would you mind explaining it in more detail please?


I'm not quite sure it is required here either, as there isn't that much mass under the jaw in this model. Usually when a character has a dewlap, we put a stretchy bone or two between the jaw and the sternum or lower neck to keep the silhouette under the jaw from bending inward when the jaw is opened or head is tilted downward. If the bone is set to squash and is placed deeper, it can give a bit of bulging out under those angles, giving it a feeling of fat under the jaw. The downside of that is that it may look odd when the head is turned a lot to the side.
Again, I'm not sure it is necessary here.

Quote:
Originally Posted by Basajaun
- Lower limbs: I made them more human-like to make things a little bit simpler for myself, do you really think I should add that ankle bone?


Imagine the leg in motion with the ankle joint staying completely stiff throughout. The ankle join of any animal is quite movable, having it "locked" will definitely look unnatural.

I imagine you're avoiding coming up with a solution to it because you like to keep the automation of the reverse foot roll rig. I'm afraid I cannot comment on how to make a reverse foot roll rig that was suited to this case more, since I'm somewhat biased - I hate it with a passion when I'm animating (and consider it more an exercise in rigging that only exists to teach students how to use certain features). We stopped using them in production early on after a few rigs and animations. Instead we use this much simpler rig from Paul Neale, that offers more control to the animator, except we use look at constraints instead of IKs; the upside of this system is that you can conveniently modify it to support more joints in the foot/ankle. (Take this with a grain of salt, as it may just be a matter of preference.)

Quote:
Originally Posted by Basajaun
- For the collar and bottom edge of the shirt, I have created a series of controls using Spline IK. Do you think this is a proper solution or is there a better alternative?


As IKchain doesn't stretch by default, you will likely have problems with the end of the chain sliding around when you animate it. (Also, whenever using IKchain, remember to assign an upnode, else it'll flip at certain angles) A more convenient stretchy spline rig can be made using a chain of bones path-constrained to a spline, the rotation/twist of each bone can be made using lookat constraint looking at a point that is constrained to the path at the same point as the next bone (this is to avoid dependency loop), and have the lookat's lookat upnode be a point on a copy of the spline offset to the side. I know it likely sounds confusing...

Alternative is to use stretchy bones instead. Either in this direction, or right angles to it, or both (similar to how bone rigs for the face work).

Or even not rig it with any bones at all and just slap a relatively stiff flex modifier on the floppy parts to introduce some jiggle.

Quote:
Originally Posted by Basajaun
- Finally, I wanted to ask you about the webbing (the vest-like thing with pouches). What do you think would be the best solution for it? Skin it directly to the existing bones? Use the cloth modifier?


Skinning would likely be the least hassle (actually, skin the shirt below, then transfer the skin to the webbing using skin wrap modifier - pick the shirt as target, then use "convert to skin" feature, then delete the skin wrap and keep the skin; this is a good way to skin clothes onto a body when you have a full model of the body under clothes), the only problem is the pockets, they look like they have mass and would jiggle. A flex modifier for them would likely be a bad solution, because that would deform them. Likely you can make bones for them with spring constraints. (When using springs, make sure you offer the animator a way to disable them as they are history dependent, meaning the scene can become unworkable with at later frames due to performance issues.)

Last edited by Zhalktis : 09-03-2013 at 12:12 PM.
 
Old 09-04-2013, 12:43 AM   #5
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Ok, the stretchy bones are in place. There is one that goes from the shoulder to the sternum, one that goes from the shoulder to the head and one more from the shoulder to the upper spine. I have also completely redone the legs; they now resemble more the anatomy of an actual frog and I've also added an additional twist bone on the thigh. For the moment I won't be including the spline IK I made for the shirt, I will skin the new parts and we'll see if I need it or not.

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Old 09-04-2013, 12:43 AM   #6
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