Zbrush rigging Zspheres issue

[Sebastien Sterling]

Hey there people, am dipping my toes into Zsphere rigging for posing, something i initially used to rig by hand.

First impressions is that it is pretty awsome, no idea what kind of volume based eveloping is taking place, but i seem to typically be able to get a lot out f it

I do have one issue that is fairly problematic, say the character is a biped,

when i rotate the arm, the finger joints seem to turn on themselves, not sure if it's the Zspheres that are literally going haywire, or if its the mesh that simply can't follow through such extreme traslations.

This may be a bit of a stretch if anyone has ever used this workflow and knows the pitfalls i would love to hear from them.

[Nic Sievers]

I have use them quite a bit, particularly a lot when I was working on Snow White and the Huntsman.  The are useful while concepting, but they are very very finicky.  I have had something like what you are talking about, only instead of them turning in on themselves I would get random 'pops' of joints.  Hard to explain, but you'll know what I mean when it comes up.

Is it actually the joints moving or is it the mesh that is folding in on itself?

If the joints of the fingers are rotating while you're actually rotating the shoulder, from what I found there is not a whole lot you can do to fix it besides actually deleting those spheres far enough up the chain and recreating them.  So if the in your case I would pretty much delete the arm and recreate.  Its vitally important as you are creating the rig to be test rotating the joints as you go along. Not every one per se, but if you create the legs I would test them before going onto the arms to make sure its 'stable'.  As you test rotate, just ctrl z to get back to default or make a layer, test, then delete. 

Hard to say what the cause of it is.  In using them I've run in to all sorts of strange issues that I feel like go unexplained why it happened.  In your case its possible on creation one of the base zpheres got rotated in a weird way.  Also recommended that when you actually use it for posing always use layers.  Several, actually.  I try to use layers for sections of the body, incase I ran into an error or the popping I could start that layer over without losing the rest.

hope that is useful,

Nic

[Sebastien Sterling]

Yep have seen popping, happens usually when i turn off adaptive skinning preview, so not the worst place for it to happen i guess.

the trouble concerning the rogue joint twisting is, i have no idea if the mesh is moving independently or if it's the spheres..

i've kind of found a sweet spot now, a point at which it is acceptable enough for me to go back and just use the regular move tool.

Thanks Nic, nice to hear info from an MD Boss :), feels like i'm taping the source. :P