Setting keyframes on bones with IK sets strange keyframes #66360

New Issue

a · 2019-07-03T03:28:47+02:00

a commented

2019-07-03 03:28:47 +02:00

System Information
Operating system: MacOS 10.14.5
Graphics card: AMD Radeon Pro 580X OpenGL Engine ATI Technologies Inc. 4.1 ATI-2.9.26

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-02 22:33, hash: 50ccbe6bb2
Worked:unknown

Short description of error
When I set a keyframe with I key only to the rotation control bone with the inverse kinematics set bone, a strange keyframe is set

Exact steps for others to reproduce the error
Look at blend files and video files{F7562968}

**System Information** Operating system: MacOS 10.14.5 Graphics card: AMD Radeon Pro 580X OpenGL Engine ATI Technologies Inc. 4.1 ATI-2.9.26 **Blender Version** Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-02 22:33, hash: `50ccbe6bb2` Worked:unknown **Short description of error** When I set a keyframe with I key only to the rotation control bone with the inverse kinematics set bone, a strange keyframe is set **Exact steps for others to reproduce the error** Look at blend files and video files{[F7562968](https://archive.blender.org/developer/F7562968/archive.zip)}

a commented

2019-07-03 03:28:47 +02:00

Added subscriber: @box_channel

a commented

2019-07-03 04:00:39 +02:00

test.mp4

test.blend

[test.mp4](https://archive.blender.org/developer/F7563029/test.mp4) [test.blend](https://archive.blender.org/developer/F7563030/test.blend)

Germano Cavalcante commented

2019-07-03 15:59:40 +02:00

Added subscribers: @JoshuaLeung, @mano-wii

Germano Cavalcante commented

2019-07-03 15:59:40 +02:00

@JoshuaLeung, can you confirm the bug?

Sebastian Parborg commented

2019-07-04 15:35:59 +02:00

Added subscriber: @ZedDB

Sebastian Parborg commented

2019-07-04 15:35:59 +02:00

I have a hard time trying to figure out what it being show cased here. What is strange? Where is this strange key frame? What is the expected result?

a commented

2019-07-04 17:11:54 +02:00

As you can see in the video, the keyframe of the rig is only in the first frame
Then move the frame and select bones for foot rotation and set keyframes with I key without rotating
Then you should have the same keyframe as the first frame because it is not rotating
However, in video, a key frame different from the first frame is set
So if you set keyframes even though you haven't moved, you will animate yourself

I made a video with an explanation
please look
IK.mp4

As you can see in the video, the keyframe of the rig is only in the first frame Then move the frame and select bones for foot rotation and set keyframes with I key without rotating Then you should have the same keyframe as the first frame because it is not rotating However, in video, a key frame different from the first frame is set So if you set keyframes even though you haven't moved, you will animate yourself I made a video with an explanation please look [IK.mp4](https://archive.blender.org/developer/F7566439/IK.mp4)

Sebastian Parborg commented

2019-07-04 18:01:13 +02:00

Changed status from 'Open' to: 'Archived'

Sebastian Parborg closed this issue

2019-07-04 18:01:13 +02:00

Sebastian Parborg self-assigned this 2019-07-04 18:01:13 +02:00

Sebastian Parborg commented

2019-07-04 18:01:13 +02:00

Ok, now I see!

Thanks for the explanation. So the issue is that even if you haven't made and changes to the bone, inserting a key frame will make the bone move.

However, upon further investigation this seems to be because you are using a Visual keying method. (Keying -> Active keying set)
This will try to evaluate constraints before setting the key value. Sadly, we can't guarantee that the IK evaluation will lead to consistent values.
So what you are observing is this. It tries to evaluate the rig with IK and save the final position of the bone. In this case the position is not the same as the one you have set, so the bone moves.

I've talked to some other devs and we do not consider this a bug. You will simply have to use a non Visual keying set to get around this.

Ok, now I see! Thanks for the explanation. So the issue is that even if you haven't made and changes to the bone, inserting a key frame will make the bone move. However, upon further investigation this seems to be because you are using a `Visual` keying method. (`Keying -> Active keying set`) This will try to evaluate constraints before setting the key value. Sadly, we can't guarantee that the IK evaluation will lead to consistent values. So what you are observing is this. It tries to evaluate the rig with IK and save the final position of the bone. In this case the position is not the same as the one you have set, so the bone moves. I've talked to some other devs and we do not consider this a bug. You will simply have to use a non `Visual` keying set to get around this.

a commented

2019-07-05 02:02:02 +02:00

I see
Thank you very much

I see Thank you very much

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Setting keyframes on bones with IK sets strange keyframes #66360