View Full Version : nobody knows how to rig arms??

01-22-2004, 08:49 PM
Hey guys, hoping somebody can help out here. Ive had a thread going for a while on the "tips and tricks" section but nobody seems to know how to do it. Im having probs rigging arms, its been an on going problem for me for years, and Ive never seen it addressed in any book, tutorial or thread, so either nobody has figured out how to rig arms or im going about it REALLY wrong. rather than retype the whole thread, if you guys could take a look at
and let me know what you think it would be a great help. Thanks all,

01-24-2004, 12:41 PM
OMG, were in big trouble, we got a whole bunch of armless characters running around. This should be a basic issue, is nobody out there that knows how to do this? please help if you can.

01-24-2004, 03:11 PM
Hard following that thread:(

But here's how I take control of arms and legs for total control (at least I haven't hit a snag yet).

When putting in skeligons I always put elbow and knee and heel IK bones.
Then in Layout I make (for sake of easy reading I will stay with just the arms) 1 main Arm_R_Null, then a hand null as child and elbow null as child, then all finger IKnulls as children of hand null.

I can keep the hand in 1 spot and move elbow from straight down to over the head and everything else holds.
If I know I will need more control I add a Shoulder IK bone in modeler (and corresponding null in layout).

Once bone limits are set, everything moves just fine in whatever position I can think of, just by moving the nulls.

It could all be tied with expressions, but that is out of my paygrade:)

I am still looking for a fill in the blank expression that goes:

If bone (blank) min movement is 3 degrees then it equals 0% on slider
If bone (same bone) max movement is 100 degrees then it equals 100% on slider

When bone (blank) moves 50% then morph (blank) moves 50%

01-24-2004, 06:10 PM
Try this, I found it extremely helpful:


01-24-2004, 09:45 PM
Looking at the PDF and it has expressions:(

Dang,gonna just have to learn them I guess.
Was hoping to go thru life without doing that:)

01-25-2004, 03:42 AM
Thanks guys.
thanks for the link. I checked it out and looks like hes got some great stuff there. unfortunately he didnt Ik the arms (at least from first glance i dont think he did, its my 6AM bedtime here so ill look again when i wake up in an hour). really great stuff though, thanks for the lead. Ive not seen people post stuff like those sliders before, but did you notice the "follower calculator"? Thought that was funny, just in case we forget how to subtract one number from another.

I used to have a setup very similar to that, but not quite as elaborate. was just one null at wrist and one at elbow to force rotation. problem was, however, that it didnt fix the fact that the arm is trying to bend in an impossible angle, and my arm would snap all around in B. Im posting a zip of the lws and lwo i rigged up real fast for show and tell. If you would be willing to, could you post a coppy of a bones setup thats workin for you? you said youve never had the issue, and id love to try to figure out why its workin so well. also, dont know of a way to reference morf mixer channels in an expression, but im sure its there, Ill look into it for ya tomorrow.
Thanks guys

01-25-2004, 03:59 AM
uh, yeah, heres the .zip

01-25-2004, 05:59 AM
The Follower Calculator is a little more complicated than simple subtraction. I found it quite useful.

He does discuss IKing the legs. You should be able to transfer much of that information to the arms.

01-25-2004, 09:54 PM
OK, now that Ive had a bit of sleep and all, I went back and looked at the scene he provides with the rig. Its a very smart setup, and think im gonna start using most of it, however the legs, and arms if you rig them acording to the legs, do pop. im attaching a .zip file to this posting which is just his sample scenes but with the foot moved foreward as if stepping and the pelvis dropped a bit at frame 1, original pose is at frame 0. if you grab the left foot and rotate in H youll see what i mean, the knee popps all over the place instead of rotating smoothly. granted, in this particular pose its not very probable that you will want the foot to rotate that way, but possible, and the real issue comes when the arms are setup like this because they are so much more poseable. Im going to try to setup a expression to handle the rotation bone I mentioned in the original thread "arms a poppin" to see if that helps, had the idea at work that perhaps LW solves for expressions after IK solutions which would fix the prob.
also, i love the idea of auto pelvis XZ positions, however do you know a way to turn it on for frame ranges where a character is walking/standing but off for times when he is sitting/jumping wihtout baking the frames? hate baking frames and then having to go back and edit something.