FCurve extrapolation ignored in whenever anything is present in the NLA #115978

New Issue

michael campbell · 2023-12-09T14:43:33+01:00

michael campbell commented

2023-12-09 14:43:33 +01:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 537.58

Blender Version
Broken: version: 4.1.0 Alpha, branch: main, commit date: 2023-11-25 22:37, hash: 1b6cd937ffc8
Worked: 3.6.3
Worked: 3.6.2

Short description of error
extrapolation ignored

Exact steps for others to reproduce the error

open attached file in 4.1 (load ui)
press play.
character stops at last keyframe even though linear extrapolation is enabled.
copy the metarig and paste it in to blender 3.62
play back now works correctly.
back in blender 4.1, disable the nla channel that has the 'walk cycle' strip on it. Now extrapolation will work properly.

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 537.58 **Blender Version** Broken: version: 4.1.0 Alpha, branch: main, commit date: 2023-11-25 22:37, hash: `1b6cd937ffc8` Worked: 3.6.3 Worked: 3.6.2 **Short description of error** extrapolation ignored **Exact steps for others to reproduce the error** 1. open attached file in 4.1 (load ui) 2. press play. 3. character stops at last keyframe even though linear extrapolation is enabled. 4. copy the metarig and paste it in to blender 3.62 5. play back now works correctly. 6. back in blender 4.1, disable the nla channel that has the 'walk cycle' strip on it. Now extrapolation will work properly.

extrapolation broken.blend

1.1 MiB

michael campbell added the

labels 2023-12-09 14:43:33 +01:00

Philipp Oeser commented

2023-12-11 10:04:47 +01:00

I think I can confirm, will check

Philipp Oeser added

and removed

labels 2023-12-11 10:05:06 +01:00

Philipp Oeser commented

2023-12-11 10:22:21 +01:00

This probably changed with 9da88301ef

So now a strip in the NLA (even if only edited and not pushed down) will always be evaluated with its Extrapolation -- Hold Hold Forward etc.).

This basically means whenever there is anything else in use in the NLA, you cannot properly use Extrapolation from the FCurves anymore...

CC @nrupsis
CC @nathanvegdahl
CC @dr.sybren

Am I missing something?

This probably changed with 9da88301efea47d184f347f2b2e54742351361d7 So now a strip in the NLA (even if only edited and not pushed down) will always be evaluated with its Extrapolation -- `Hold` `Hold Forward` etc.). This basically means whenever there is anything else in use in the NLA, you cannot properly use Extrapolation from the FCurves anymore... CC @nrupsis CC @nathanvegdahl CC @dr.sybren Am I missing something?

Philipp Oeser added

and removed

labels 2023-12-11 10:22:30 +01:00

Philipp Oeser changed title from ~~extrapolation ignored in 4.1, works fine in 3.6~~ to FCurve extrapolation ignored in whenever anything is present in the NLA

2023-12-11 10:23:08 +01:00

Sybren A. Stüvel commented

2023-12-11 11:26:40 +01:00

Thanks @lichtwerk for the analysis.

I can't seem to reproduce the bug with the steps above. When I copy-paste the armature into Blender 3.6.5 it behaves the exact same way (linear motion stops after the last key). Pasting into Blender 3.5 crashes Blender for me.

To reproduce this reliably, IMO it's better to have a 3.6 file that works as expected on 3.6, and when opened in 4.1-alpha shows different extrapolation behaviour. So that's what I made, with just a rolling Suzanne (easier to debug than an entire rig). I built the file with Blender 3.5, which shows the expected behaviour (FCurve extrapolation is used when the Action is being extrapolated), while Blender 3.6 already shows the "new" behaviour (NLA "Hold" literally holds the last frame, rather than extrapolating).

I can confirm that 9da88301ef caused this change, though. @nrupsis do you have time to look into this? This could be a good one to fix in 3.6-LTS.

Thanks @lichtwerk for the analysis. I can't seem to reproduce the bug with the steps above. When I copy-paste the armature into Blender 3.6.5 it behaves the exact same way (linear motion stops after the last key). Pasting into Blender 3.5 crashes Blender for me. To reproduce this reliably, IMO it's better to have a 3.6 file that works as expected on 3.6, and when opened in 4.1-alpha shows different extrapolation behaviour. So that's what I made, with just a rolling Suzanne (easier to debug than an entire rig). I built the file with Blender 3.5, which shows the expected behaviour (FCurve extrapolation is used when the Action is being extrapolated), while Blender 3.6 already shows the "new" behaviour (NLA "Hold" literally holds the last frame, rather than extrapolating). I can confirm that 9da88301ef caused this change, though. @nrupsis do you have time to look into this? This could be a good one to fix in 3.6-LTS.

115978-extrapolation_broken-35.blend

130 KiB

Philipp Oeser commented

2023-12-11 11:33:55 +01:00

Sorry for not updating the description (I updated it now).

The breaking change is already in 3.6.3.

So the steps are still valid, you have to paste into 3.6.2 though (not 3.6.3) to see it behave "properly".

Sorry for not updating the description (I updated it now). The breaking change is already in 3.6.3. So the steps are still valid, you have to paste into **3.6.2** though (not 3.6.3) to see it behave "properly".

Nate Rupsis commented

2023-12-11 16:23:21 +01:00

@dr.sybren I'll add it to my todo list.

❤️ 1

michael campbell commented

2023-12-11 19:38:27 +01:00

Hi, if it helps narrow down the cause of extrapolation not working on the active action when there are pushed down NLA strips active, the version of Blender 3.63 that is still working when I paste into it from 4.1 is:

Hi, if it helps narrow down the cause of extrapolation not working on the active action when there are pushed down NLA strips active, the version of Blender 3.63 that is still working when I paste into it from 4.1 is: ![image](/attachments/46d4a0ab-24c7-47dd-9f10-875a17b6dba0)

image.png

27 KiB

Wayde Moss commented

2023-12-11 21:51:54 +01:00

At a glance, it looks like a missed copy/paste:

in 9da88301ef : (anim_sys.cc, L3238) should be
r_action_strip->flag |= NLASTRIP_FLAG_USR_INFLUENCE | NLASTRIP_FLAG_NO_TIME_MAP;

original: https://projects.blender.org/blender/blender/pulls/107281/files

At a glance, it looks like a missed copy/paste: in 9da88301efea47d184f347f2b2e54742351361d7 : (anim_sys.cc, L3238) should be `r_action_strip->flag |= NLASTRIP_FLAG_USR_INFLUENCE | NLASTRIP_FLAG_NO_TIME_MAP;` original: https://projects.blender.org/blender/blender/pulls/107281/files

👍 1 🚀 2

Nate Rupsis referenced a pull request that will close this issue

2023-12-20 17:23:32 +01:00

Fix #115978: FCurve extrapolation ignored in NLA. #116382

Nate Rupsis was assigned by Christoph Lendenfeld

2024-01-04 14:13:30 +01:00

Christoph Lendenfeld commented

2024-01-04 14:13:45 +01:00

@nrupsis assigned you since you have a PR in the works

Nate Rupsis referenced this issue from a commit

2024-01-11 18:44:56 +01:00

Fix #115978: FCurve extrapolation ignored in NLA.