Unpredictable Arcs
interpolator
I'm doing some animations recently and run into Bones doing unpredictable flips and rotations. For example the right arm starts at relaxed position at the side of the body, reaches up and touches the left ear. Then return to original position.
There are no IK solvers, strictly FK.
Standard arm structure with clavicle->Bicep->forearm.
On returning to original position the arm tends flip out of wack and arms wildly before settling to final frame.
The bones all have Euler XYZ as default rotation. I can solve this by setting the bones to use Smooth Rotation; but then I don't have access to the keyframes in the curve editor. I've run into this with Biped as well in similar situations and usually resort to keying it out manually, sometimes ending up with a stop motion feel. Which isn't best for everything.
How do you animators deal with this?
There are no IK solvers, strictly FK.
Standard arm structure with clavicle->Bicep->forearm.
On returning to original position the arm tends flip out of wack and arms wildly before settling to final frame.
The bones all have Euler XYZ as default rotation. I can solve this by setting the bones to use Smooth Rotation; but then I don't have access to the keyframes in the curve editor. I've run into this with Biped as well in similar situations and usually resort to keying it out manually, sometimes ending up with a stop motion feel. Which isn't best for everything.
How do you animators deal with this?
Replies
I think this sometimes happens if you copy a keyframe from the start to the end of an animation, because it takes the absolute rotation from the copied frame rather than the relative - you might find it's doing a large negative translation (like -350 degrees instead of +10 degrees). This is a value you can check in track view too.
How would you achieve the same position at the end without copying the frame from the beginning? I guess what I'm really asking is whats the proper technique to create a good cycling animation with Max Bones or Biped? Before now I make a cycle and then copy it so there are two repitions of the cycle and then crop it down to a good cycle with the timeline.
Like I said, this works with the biped's TCB controller, but might still be worth a try with euler as well.
Vailias - I'll try that with the next round of animations.
eric - yeah I remember something like that now that you mention it. I don't know how it would have helped if I remembered it. I think I'm just really rusty animating with maxbones
hyrumark - I tried it and it didn't seem to do much. But I'll remember it when I animate with biped in the future.
mop - yeah I tried that the first time around and the little hiccup when the cycle turns around remained, but after I set the bones to smooth and then back to euler, that worked. well sort of, auto curves sets the bias bar to the tangent at the key, which is the same as setting slow in and out manually for the key.
I got alot of refreshing to do.
I'm doing some animations recently and run into Bones doing unpredictable flips and rotations. For example the right arm starts at relaxed position at the side of the body, reaches up and touches the left ear. Then return to original position.
There are no IK solvers, strictly FK.
Standard arm structure with clavicle->Bicep->forearm.
On returning to original position the arm tends flip out of wack and arms wildly before settling to final frame.
The bones all have Euler XYZ as default rotation. I can solve this by setting the bones to use Smooth Rotation; but then I don't have access to the keyframes in the curve editor. I've run into this with Biped as well in similar situations and usually resort to keying it out manually, sometimes ending up with a stop motion feel. Which isn't best for everything.
How do you animators deal with this?
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Use IK and bake them to FK
If that's not the problem it could also be gimbal locking: http://www.anticz.com/eularqua.htm which is a far more annoying problem to fix afterwards.