View Full Version : Quadraped rigging help

Ryan Roye
04-07-2011, 09:19 PM
I'm not too optimistic about finding a solution to this, but I thought I'd ask here as a shot in the dark.

It might get too texty for me to explain how my rig operates and what the problem is so I posted a video (1:30 in length) showing the issue visually:

Attached is a proxy version of my Silgrarian rig similar to the one shown in the video.

Rigging problem video (http://www.youtube.com/watch?v=LQI4Q6EMMok)

NOTE: IKstop is NOT the culprit, i've tried working around the IKstops and get the same issue. I'm only really concerned with foot placement right now.

04-07-2011, 10:48 PM
Unfortunately thats just IKB for you. Ive pointed this out myself on a few occasions over the years, that IKB will give a different result when performing the same action repeatedly, and also that, even using the fix points, that IK contact points have a habit of slipping around.

You can play with IKBs "resolution/precision" option (I forget exactly what its called and where it is... its the option that tells IKB how precisely to try to solve the IK... its in there). That will sometimes help out, but often doesnt get you the whole way there.

Going with straight LWIK is certainly gonna be your ebst bet for getting predictable results out of any IK setup... the problem you face with this character ofc, is that LWIK doesnt do so hot on 3 bone chains... requiring you to pretty much use a 2 bone IK chain with the third bone operating in FK (though it can also use target item too, or some other modifier/expression if you're wanting a little more IK like automatic posing).

Ryan Roye
04-08-2011, 05:10 AM
Thanks RH. I'm not looking for perfect results as my work is just hobbyist stuff, but it'd be nice to not get a headache while animating from tedious corrective positioning. I animate in 20 frames per second which helps.

The issue with mixing FK/IK with 3-bone leg placement is that if I do happen to move the leg its hard to avoid clipping and positioning issues like shown in the video. I'll experiment with it more though. I haven't expended all my options yet like channel follower and what you mentioned so we'll see how it goes.

I will post back here if I whip up some kind of solution in case anyone else runs into the same problem. If not, I'll probably use this rig one more time and then scrap it as the next project this guy appears in absolutely requires a better rig (3+ months down the road).