F-curve editor displays incorrect curve for reversed NLA strips #35708

New Issue

Paul R · 2013-06-11T12:32:08+02:00

Paul R commented

2013-06-11 12:32:08 +02:00

Operating System, Graphics card
Linux SuSE 12.2 (x86_64)
NVidia GTX560ti (official driver)

Blender version with error, and version that worked
Broken: 2.67b - 2.91 and recent buildbot binaries

Short description of error
Reversing a strip in the NLA editor makes the f-curve editor display animation curves incorrectly. This is only a UI/display issue - object will still animate as expected.

Steps for others to reproduce the error (preferably based on attached .blend file)

add a couple of keyframes to an object and switch to NLA
turn action into action strip (snowflake icon)
in the strip properties, enable 'Reversed'
go into edit/tweak mode for the strip then switch to f-curve editor
animation curves are drawn incorrectly

#35708-nla-reverse-display-issue.blend

Normal:

Reversed:

**Operating System, Graphics card** Linux SuSE 12.2 (x86_64) NVidia GTX560ti (official driver) **Blender version with error, and version that worked** Broken: 2.67b - 2.91 and recent buildbot binaries **Short description of error** Reversing a strip in the NLA editor makes the f-curve editor display animation curves incorrectly. This is only a UI/display issue - object will still animate as expected. **Steps for others to reproduce the error (preferably based on attached .blend file)** - add a couple of keyframes to an object and switch to NLA - turn action into action strip (snowflake icon) - in the strip properties, enable 'Reversed' - go into edit/tweak mode for the strip then switch to f-curve editor - animation curves are drawn incorrectly [#35708-nla-reverse-display-issue.blend](https://archive.blender.org/developer/F9264180/T35708-nla-reverse-display-issue.blend) Normal: ![image.png](https://archive.blender.org/developer/F9264177/image.png) Reversed: ![image.png](https://archive.blender.org/developer/F9264174/image.png)

Paul R commented

2013-06-11 12:32:08 +02:00

Changed status to: 'Open'

Paul R commented

2013-06-11 16:40:48 +02:00

%%%Just to clarify, this is a longstanding issue with Blender. Not just with recent releases.%%%

Joshua Leung commented

2013-06-12 15:05:24 +02:00

%%%Checking the code, it looks like the potential for this sort of thing to happen is already known/marked as something to be fixed.

The cause of this is in tweak mode, keyframes get some mapping applied so that they appear in global time where the NLA strips will map them to be. However, in the case of reversed strips, this turns out to be quite problematic when drawing the graphs as the keyframes themselves are still stored/drawn in the normal forward order. Best/easiest solution would probably be to just ignore the reversing part when applying this mapping (though the disadvantage is that for consistency between graph and dopesheet, keyframes in dopesheet wouldn't get reversed either, even though it doesn't affect those, thus potentially making things a bit more confusing when trying to figure out which keyframes to retime there).

As a workaround, click the pin icon beside the action name (in the channel list) while in tweakmode to disable the time remapping of keyframes in tweakmode when dealing with such cases.%%%

%%%Checking the code, it looks like the potential for this sort of thing to happen is already known/marked as something to be fixed. The cause of this is in tweak mode, keyframes get some mapping applied so that they appear in global time where the NLA strips will map them to be. However, in the case of reversed strips, this turns out to be quite problematic when drawing the graphs as the keyframes themselves are still stored/drawn in the normal forward order. Best/easiest solution would probably be to just ignore the reversing part when applying this mapping (though the disadvantage is that for consistency between graph and dopesheet, keyframes in dopesheet wouldn't get reversed either, even though it doesn't affect those, thus potentially making things a bit more confusing when trying to figure out which keyframes to retime there). As a workaround, click the pin icon beside the action name (in the channel list) while in tweakmode to disable the time remapping of keyframes in tweakmode when dealing with such cases.%%%

Julian Eisel commented

2014-12-23 05:09:46 +01:00

Added subscriber: @JulianEisel

Julian Eisel commented

2014-12-23 05:09:46 +01:00

Checking the code, it looks like the potential for this sort of thing to happen is already known/marked as something to be fixed.

AKA: "This is a ToDo, not a bug"(tm) :P

This should have been a ToDo rather than a bug for 1.5 years...

> Checking the code, it looks like the potential for this sort of thing to happen is already known/marked as something to be fixed. AKA: "This is a ToDo, not a bug"(tm) :P This should have been a ToDo rather than a bug for 1.5 years...

Joshua Leung was unassigned by Sybren A. Stüvel

2020-11-09 18:37:26 +01:00

Adam Janz commented

2022-06-03 00:29:14 +02:00

Added subscriber: @AdamJanz

Adam Janz commented

2022-06-03 00:49:54 +02:00

Just discovered this in 3.2 beta. Very bizarre behavior indeed. I thought the curves were actually broken, but it's nice to know it's just a display issue. Would be so great to have this addressed as it makes editing the curves of reversed NLA clips impossible. For now, I will have to manually mirror the keyframes in a new clip rather than using the "Reverse" option. Thanks to the devs for your continued improvement of Blender!

Philipp Oeser removed the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

F-curve editor displays incorrect curve for reversed NLA strips #35708