IK Control Instance's "SmoothTime" property is broken

Bug Reports Engine Bugs
#1

Reproduction Steps

“SmoothTime” property causes weird behavior (twitching movement & not able to reach IK target) when its value is greater than 0 (means enabled)
e63f5e727203d0550fc178ca8573566351c4433c

Expected Behavior

“SmoothTime” property should make IK movement smooth and reach target’s position fluently in a set of time

Actual Behavior

  • Twitching movement
  • Not able to reach IK target

Workaround

  • No workaround at the moment
  • Turns off SmoothTime property for fully functional IK as of right now

Issue Area: Engine
Issue Type: Other
Impact: Moderate
Frequency: Constantly

5 Likes
Inverse Kinematics Control Instance for animation is now in Beta!
#2

I’ve experienced this issue about a week ago, and I know a little bit about the issue.

  • Resetting the Transform will cause it to do what’s shown in the picture.
  • Playing an animation on the motor will cause issues.

My workaround (for the time being):

  • Set SmoothTime to 0.
1 Like
#3

Hi, thanks for reporting this. I haven’t been able to reproduce this in my own testing with IKControl and SmoothTime. Can you describe how you’re setting up the IKControl, or better yet do you have a script or test places that reproduces this issue?

1 Like
#4

Hi, Thank you for following up! Please find the repro test place below -
ik_twitching.rbxl (34.4 KB)

Basically to reproduce this issue is to enable IK instances during some of the motor6D’s C1 / C0 is being changed, for example head follows camera direction :bowing_man: Also thanks for SubtotalAnt8185 for the further information and we can now pinpoint the exact issue :raised_hands: Everything used to function perfectly and the issue seems to be started to happened around 1 week ago

#5

Hi, thank you for the report.
I’ve investigated and prepared a fix. It should be live sometime next week.

As a side note, I would suggest not updating a motor6D’s C0/C1 each frame. Although this issue is now fixed, the animation system is not built with that in mind and there might be other issues or in general less performance.

Thanks

2 Likes
#6

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.

#7

Can confirm this is fixed! Thanks again for the report.

2 Likes