Dual quaternion skinning?

Rigging
#1

Hey guys,

I’ve been looking at some of the newer Maya features and saw dual quaternion skinning on one of the autodesk area blogs…

Dual quaternion skinning: Traditional smooth skinning in Maya uses linear skinning to make a mesh follow a character’s joints. In areas such as a wrist or elbow, this method can result in a ‘bow tie’ or ‘candy wrapper’ effect where the mesh loses volume as a bone twists on its axis. Dual quaternion is a new method of smooth skinning designed to eliminate these undesirable deformation effects. A new menu in the Smooth Bind Options window (and in the skinCluster) lets you select whether to use classic smooth skinning, dual quaternion skinning, or blend between both methods at a vertex level on the same character.

Kind of picked up my interest there. So I’m wondering, has anyone been using this, and does it deliver? I’m upgrading to 2012 soon, a bit curious…

#2

there have been a couple of other threads about dq skinning… you might want to check them out too for more info.

in my experience, dq skinning looks awesome on certain areas but can make other areas hold too much volume. i had problems with the chest/shoulders when character put their arms above their heads - the pectoral area looked like a damned wing sticking out from the character instead of deforming smoothly.

basically my opinion is that it’s cool but not useful enough to replace standard linear interpolation unless you can blend between the two. for the game that i was working on at the time, the cost was prohibitive to support blending between linear interpolation and dq in-engine.

#3

Yeah thats the problem - you have to be able to blend between the two skinning types which for us in the games industry is prohibitive. It’s a real shame because I end up carrying around so many hacky deformer bones to resolve things DQ could fix easily!

#4

I use it. (film not games.) I set it to “Weighted Blend” and flood to 0.3 or 0.4 and adjust accordingly. Usually a uniform flood is enough for my purposes.

I haven’t really tested properly to see if it was a problem with my options, but I noticed that it doesn’t mirror properly when doing “mirror weights”. It flipped both sides, while the rest of the skin weights mirrored properly. So double-check that before you paint any major details.

#5

I’m in TV… sounds like more leeway here than rigging for games, though I’d like to tackle the challenge someday.

Great heads up about the mirror issues. I’ll watch out for that when I get the chance to test this thing out. Does sound like its more useful for certain areas than the whole character rig.

I’ll look up those other threads too. Cheers for the pointers, guys.

#6

We used DQ skinning in our last title. For the most part it’s pretty good, especially for maintaining volume on forearms and shoulders using fewer joints.

To get around the bulging effect in the armpit/latissimus and crotch areas you have to reduce the vertex complexity/density and tighten the influence range.

It’s great for knees and elbows (and eyelids).

Mark

#7

[QUOTE=Nahaz;13706]We used DQ skinning in our last title. For the most part it’s pretty good, especially for maintaining volume on forearms and shoulders using fewer joints.

To get around the bulging effect in the armpit/latissimus and crotch areas you have to reduce the vertex complexity/density and tighten the influence range.

It’s great for knees and elbows (and eyelids).

Mark[/QUOTE]

This was for a game project right?
Do you know what the code team’s response was to implementing DQ skinning in code and the effects it had on the game in terms of frame rate and computing overhead?

#8

[QUOTE=snoutling;13727]This was for a game project right?
Do you know what the code team’s response was to implementing DQ skinning in code and the effects it had on the game in terms of frame rate and computing overhead?[/QUOTE]

Not sure how easy it was to implement. I think the overhead was negligible, especially since we could use fewer bones. It must have some impact however, there was talk of removing it on the handheld SKU.

#9

hey guys , for armpit/latissimus bulging if I can not change the mesh what would be good joint positions for helpers? I am dealing with a pretty well defined mesh and I can only use one skin solver, DQ only, and joints only.
thanks a lot
Yury

#10

Try just playing around with it till you find one that works? No silver bullet if the mesh has problems…