I am using Blender 2.75. So I have an armature for a pig. I used IK to have the legs always bend (a certain direction using a pole target) to connect with the target bone. I am pretty sure this is all set up right. I have animated the location (only) of the target bone in an attempt to make a walking animation.

However, it seems the IK is lagging behind when changing what frame of animation I am on. This is also tricky because in the final animation, I will be using an online render farm, which sends one frame to each render node, and does not "play" the animation up until that point, only says, "jump to this frame and render it".

In the attached gif you can see that I have to set the frame twice to make the IK point to the target bone properly. How would I force the IK to not lag behind and point to the target on its first try?

Note: I'm not worried about the IK not stretching to reach the target bone when it is too far away, that is intentional.

IK lagging

Here is the blend file that I used to record the gif with (with keyframes):

  • $\begingroup$ What kind of computer do you have? Your system could just be having issues processing the distortion of the mesh. $\endgroup$ – Shady Puck May 4 '16 at 0:55
  • $\begingroup$ @ShadyPuck 3GHz Core 2 Duo 2GB RAM (Blender says it is using 445MB). However, earlier today I was testing this out on an 4th gen i5 16GB RAM and GTX 970, with the same problem. Also last night when I tested it on the online render farm all of the computers that were rendering my project had this issue. So probably not processing power. The mesh is deforming properly, just the IK bones are not pointing at the target properly. $\endgroup$ – Gliderman May 4 '16 at 1:01

You've got many dependency cycle into your Rig, as you can see on console : enter image description here

This is because you add a limit distance between your IK target and bone that have the IK constraint. Delete your limit distance constraint, and everything will be find.

(Why exactly you added this constraint ?)

  • $\begingroup$ Sorry that it took a while to reply. I just tried removing all of the limit distances (which to answer your question, I had in there so that while I'm animating, I won't lose them), and it did not resolve the issue. I even tried saving the file with them removed, and then reopening it, but it did not help. Blender is still lagging behind on the IK update when I change what frame of animation I am on (exact same result as the gif I included in the OP). $\endgroup$ – Gliderman May 6 '16 at 20:44
  • $\begingroup$ Fiddled with it some more, and apparently you need to rebuild the IK constraint after removing the bone constraint(s) that affect bones that the IK used. I would recommend adding that to your answer. :) Thanks for your help. $\endgroup$ – Gliderman May 6 '16 at 22:26

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