Elbows!

[gregh1988]

Hi,

I have a character that I am having some problems with. I am using the OK Samurai technique of multiple takes on top of a standard arm position and blending them in. Th problem I am having is that each time I get an arm around shoulder height the elbow position keeps raising almost as if the elbow has gravity applied to it. All looks OK at one point and then when I move on to animating another part or take the blow gets out of position with some odd looking  performance.

This is driving me mad. Any one else had a similar problem and found a solution?

Thanks in advance

Glenn

[Jim Acquavella]

Does your puppet use sticks to add rigidity to the mesh?  It would be helpful if you could direct message me a link to your puppet in order to evaluate the result.  Or, a screen recording of the problem?  Thanks.

[gregh1988]

Jim, Yes I have sticks employed in the arms.

During Positioning / Record:

During Playback:

Any help you can offer would be appreciated. Most confusion and frustrating!

Glenn

[DanTull]

One thing you can try and this is with the caveat that I consider it a workaround and not a solution is to put a draggable handle on the elbow as well so its position will be fixed by the recording instead of determined by the behavior runtime (which as you noticed here can result in different results from the original, unfortunately in this case). That does mean more manual positioning work as well, so again, it is just a workaround.

Dan Tull

[gregh1988]

Thanks Dan.

I have put fixed points on the elbows to get me through this piece of work but really want to get to a long term solution as this is somewhat restricting.

Glenn

[Jim Acquavella]

Are you using the Dragger to move the hand there instantaneously, or does it animate to that position?  If it travels instantaneously using a take appearing with the dragger position set, it is likely the calculated mesh to warp the hand to that position has two different solutions.  It would help if you quickly animated it to that position as you would expect the hand to travel to avoid the other path.  That would involve moving the pictured hand out and away from the body, then around and up to the desired position.  In the future, we are considering adding rotation constraints that would help avoid these uncomfortable and unnatural joint positions.  Until then, hopefully these workarounds can help you avoid these puppet contortions.

[gregh1988]

Thanks Jim,

I have tried both animating live and setting the dragger position and it seems to be the same behaviour. Interestingly I have also had its work OK and then on export / render it changes to the odd behaviour!

Moving the hand out and away and then up can look really odd.

Is there anything else I can do in setting up the rigging of the puppet to help this?

I can make it work with the fixed / handle elbow (this simply restricts what I can do with the puppet) but as you mention it would be really good to have rotation constraints to avoid this int the future.

Thanks for your help anyhow.

Glenn

[Jim Acquavella]

The only other suggestion that may help would be to create your puppet with straight arms, like our Chloe template.  Because your puppet has a slight elbow bend, that may be influencing the puppet mesh to choose one path over another.

[gregh1988]

Thanks again Jim. I will give that a try and see if it helps.

Appreciate your help.

Glenn