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Bendy Bone Parameters excluded from "In-Betweens" and "Action Constraints"
Open, Needs Triage by DeveloperPublic


System Information
Operating system: Win 10 Home
Graphics card: Nvidia 960M

Blender Version
Broken: (2.80, 2.81)

Currently the "In-Betweens" and "Action Constraints" functions within blender do not take the "Bendy Bone" parameters into consideration with keyframes

The timeline, however does take the parameters into consideration with keyframes. The image and file below show the results.

The keyframing setting used was the "whole character" selection which includes the bendy bone parameters.

---Steps to re creating this problem below---


Create a bendy bone


Select the (stretch -to) middle bone in the bendy bone


On frame 1 keyframe the bendy bone using Whole character (selected bones only)


Notice that all of the bendy bone properties except the “scale in x”, “Scale in y”, “Scale out x”, “scale out y” don’t get highlighted? (Be sure to click “animate property” on ALL of the scaling options too).


Manipulate every parameter in the “Bendy Bone” section.


Scrub the “timeline” between the two frames. Notice that all of the parameters for the bones will change from maximum to minimum?


Move to your final frame, and select the “in-betweens” function from the pose menu.


Click your task bar below to make the menu stay open, as shown in the attached image.


Scrub the in-betweens bar from 0 to 1 and notice that (None) of the bendy bone parameters are taken into consideration.

This problem also persists if you attempt to use an action constraint as well!


The Bendy bone properties of the stretch-to bone inside Bendy bones cannot be animated with Action constraints, or altered by the “in-betweens” function in Blender. I have also tried the same test in Blender 2.81 as well.

  • Addition as of 11/21/2019: Action Constraints in Blender 2.81 (don't work at all anymore it seems). So you may not even get to reproduce the issue unless you specifically use Blender 2.8**



Event Timeline

If the team is still unsure, I can make a bigger demonstration in a few hours. I am adamant about getting this fixed, so I can release a facial rigging addon that involves animating (all) of the bendy bone properties with Action Constraints with just a click.

Sybren A. Stüvel (sybren) lowered the priority of this task from Needs Triage by Developer to Needs Information from User.Thu, Nov 21, 12:18 PM

Please update the task so that it follows the bug reporting guidelines. As it is now, it has no steps to reproduce the issue.

Darryl F Neal (dfneal38) raised the priority of this task from Needs Information from User to Needs Triage by Developer.Fri, Nov 22, 3:07 AM
Darryl F Neal (dfneal38) updated the task description. (Show Details)

I have now added steps to recreate the issue. It occurs in Blender 2.81 as well.