Thanks in advance for any help anyone can provide with this frustrating problem.
I’ve been animating in Maya for years (using keyframes and dynamics) but I’ve never used joints and IK.
I’ve built a model and rigged it. It’s a rigid “mechanical” construction with 9 separate moving parts, which pivot and slide. (Picture something like a crane arm or bulldozer attachment: straightforward “mechanical arm” type model.)
I’ve made 3 nurbs circles as “handles” to control the animation, which are connected either to “root” joints or to ikHandles. I use a combination of straightforward Maya parenting, parent constraints, point constraints and pole vector constraints to connect everything together. A few of the joints have their motion constrained to certain axes or to certain end points/start points.
It all works perfectly: I can grab any of the 3 NURBS “handles” and move them, and all the connected pieces all move the right way.
However there’s a big problem when I start animating:
I move along the timeline and set keyframes, moving the NURBS “handles” to adjust the position of the model. It all looks great, and each frame is “correct” when I move the slider to that frame, but in the animation, nothing moves. All the frames are exactly the same: Maya simply renders the current frame over and over.
Eventually I figured out that the problem had to do with the NURBS “handles” moving, and the model’s ikHandles and joints not following. When I stopped using the NURBS “handles” and grabbed the ikHandles directly, setting keyframes with those, then suddenly my animation was working.
But there were still problems: certain portions of the model move, and others don’t. Again, everything looks perfect, frame by frame, when I manually view each frame using the timeline. But the animation ignores certain components of the model, which simply don’t move in the rendered frames; they stay in the positions they’re in when I look at the current frame (the frame I was looking at when I hit “batch render.”)
As I mentioned, I’m using a combination of different constraints, with actual “parenting” kept to a minimum. I’m not using Animation Layers, “weighting,” or Driven Keys at all.
Can somebody help me begin to figure out what’s going wrong? Please let me know if there are any important missing details in my story. (I appreciate everyone’s patience with a skeleton “newbie.”) Thanks very much.
ADDENDUM:
To make this 100% clear: If I set up my animation, keyframing the movement of the NURBS “handles” (circles parent-constrained to ikHandles), and then output it by manually advancing each frame and manually “rendering current frame,” and then stringing those frames together, the result is perfect—everything moves correctly. But if I “batch-render” the frames in question, the model doesn’t move (although the non-rendering NURBS-circle “handles” do).