@Sybren A. Stüvel (sybren) or @Joshua Leung (aligorith), can you confirm this bug? (I'm not sure how these tools work).

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.

@Darryl F Neal (dfneal38) with "the in-betweens function", I'm assuming you mean "Push Pose from Rest Pose" and "Relax Pose to Rest Pose". The behaviour of these can be found in [the pose_slide_rest_pose_apply() function](https://developer.blender.org/diffusion/B/browse/master/source/blender/editors/armature/pose_slide.c$659), which shows that this isn't implemented for bendy bones yet. As such, it's not a bug, but simply a missing feature.

As far as the Action Constraint goes, the manual states:

Also note that only the object transformation (location, rotation, scale) is affected by the action, if the action contains keyframes for other properties they are ignored, as constraints do not influence those.

Unless I'm mistaken, this means that also the Action Constraint doesn't support bendy bone properties.

I've marked the task as a 'To Do', because it doesn't appear to be a bug. If I drew the wrong conclusions, please let me know.

In T71002#824343, @Sybren A. Stüvel (sybren) wrote:

I've marked the task as a 'To Do', because it doesn't appear to be a bug. If I drew the wrong conclusions, please let me know.

I had the problem marked as a bug, because the timeline can easily key-frame the parameters. My question is, if the timeline can animate a bone parameter, then why can't action constraints do the same? That sounds counter intuitive.

In order for me to properly animate this, i would literally need to create bone drivers onto the bendy parameters and then assign an action constraint to those additional bones. This means if i plan to animate a face, i would need an action constraint to run the bone pose and additionally the the bone pose that has drivers! That's super redundant for something that should be so simple.

My point is that bendy bones are bones, and action constraints are meant to be used on bones. Bendy bone properties should be possible to animate through this constraint by default. (Not being a bug would be sort of like saying a car with an engine, cannot accelerate yet). Don't you think?

Not to mention, specifically bendy bones can be used to rig faces with zero weight painting. I wanted to demonstrate this feature in a video and link it to a few places. Its especially helpful when a character asset has a proprietary rig and you need to quickly rig the face. (You can parent the bendy rig to the body rig, skipping hours of misery).

I wish that "intuitive behaviour" meant that it was also implemented. Unfortunately that's not the reality.

Not being a bug would be sort of like saying a car with an engine, cannot accelerate yet.

I would say it's like a car that works just fine but is a bit spartan, and then someone added a radio to it to make the trip a bit more pleasant, but which can only receive two radio channels. Sure, it's limited, but it works.

Maybe it's simple to implement, but the fact is that currently it isn't. It's an ommission, and in your case it seems to be a pretty big one, but it's not a bug.

In T71002#824656, @Sybren A. Stüvel (sybren) wrote:

I wish that "intuitive behaviour" meant that it was also implemented. Unfortunately that's not the reality.

Not being a bug would be sort of like saying a car with an engine, cannot accelerate yet.

I would say it's like a car that works just fine but is a bit spartan, and then someone added a radio to it to make the trip a bit more pleasant, but which can only receive two radio channels. Sure, it's limited, but it works.

Maybe it's simple to implement, but the fact is that currently it isn't. It's an ommission, and in your case it seems to be a pretty big one, but it's not a bug.

I mean its fine. So I take it other Blender 2.8 features are going to be whats being worked on for now, and when would you expect "extra" stuff to be looked at? I mean in 2020 assuming.