Inconsistency in the behavior of 'Jump to next/previous keyframe' operator #100493

New Issue

Amélie Fondevilla · 2022-08-19T09:32:42+02:00

2022-08-19 09:32:42 +02:00

System Information
Operating system: Linux-5.4.0-124-generic-x86_64-with-glibc2.31 64 Bits
Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.47.03

Blender Version
Broken: version: 3.3.0 Beta, branch: Unknown, commit date: Unknown Unknown, hash: rBUnknown
Worked: as far as I know, none.

Short description of error
When calling the 'Jump to next/previous keyframe' operator, there are inconsistency of behavior depending whether the active object is a Grease Pencil one or not.
For standard keyframes, it jumps to next keyframe if the object is active, regardless of if the object or any of its channels are selected.
For grease pencil layers keyframes, it jumps to next keyframe only if the layer channel is selected.

Exact steps for others to reproduce the error
Reproduce the bug :

Open a new blender file,
Add one grease pencil object with two keyframes,
Add one 3D mesh (for example) with two keyframes (at different frames than the grease pencil ones),
Try to jump to next or previous keyframes, standard shortcut : up/down arrow in the viewport.

issue_jump_to_next_keyframe.mp4

**System Information** Operating system: Linux-5.4.0-124-generic-x86_64-with-glibc2.31 64 Bits Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.47.03 **Blender Version** Broken: version: 3.3.0 Beta, branch: Unknown, commit date: Unknown Unknown, hash: `rBUnknown` Worked: as far as I know, none. **Short description of error** When calling the 'Jump to next/previous keyframe' operator, there are inconsistency of behavior depending whether the active object is a Grease Pencil one or not. For standard keyframes, it jumps to next keyframe if the object is active, regardless of if the object or any of its channels are selected. For grease pencil layers keyframes, it jumps to next keyframe only if the layer channel is selected. **Exact steps for others to reproduce the error** Reproduce the bug : - Open a new blender file, - Add one grease pencil object with two keyframes, - Add one 3D mesh (for example) with two keyframes (at different frames than the grease pencil ones), - Try to jump to next or previous keyframes, standard shortcut : up/down arrow in the viewport. [issue_jump_to_next_keyframe.mp4](https://archive.blender.org/developer/F13403344/issue_jump_to_next_keyframe.mp4)

Amélie Fondevilla commented

2022-08-19 09:32:42 +02:00

Added subscriber: @amelief

Amélie Fondevilla commented

2022-08-19 09:41:51 +02:00

Added subscribers: @mendio, @pepe-school-land

Amélie Fondevilla commented

2022-08-19 09:41:51 +02:00

@pepe-school-land @mendio
I would like some user feedback on this. AFAIK, this behavior was always here, but it was not really visible because the grease pencil layer keyframes were not displayed with the 'regular' keyframes in the main dopesheet.
What do you think the behavior should be ?

In my opinion the jump should at least disregard selection in grease pencil layer channels if it disregards selection of other types of channels. But that change may be confusing for grease pencil users.

@pepe-school-land @mendio I would like some user feedback on this. AFAIK, this behavior was always here, but it was not really visible because the grease pencil layer keyframes were not displayed with the 'regular' keyframes in the main dopesheet. What do you think the behavior should be ? In my opinion the jump should at least disregard selection in grease pencil layer channels if it disregards selection of other types of channels. But that change may be confusing for grease pencil users.

Pierre Schiller commented

2022-08-19 09:55:19 +02:00

Added subscriber: @PierreSchiller

Pierre Schiller commented

2022-08-19 09:55:19 +02:00

When a 2d animator sets main keyframes (aka reference keys), this function to "jump to next keyframe" is a quick solution to "flip pages back and forth" (just a figure of speech). The Jump to previous/next keyframe" should target all layers not just the current GP layer.

There can even be an operator that targets this from a custom (ie. hardware buttons in any stylus tablet) shortcut:
Insert Blank keyframe (all layers) /// bpy.ops.gpencil.blank_frame_add(all_layers=True)

When a 2d animator sets main keyframes (aka reference keys), this function to "jump to next keyframe" is a quick solution to "flip pages back and forth" (just a figure of speech). The Jump to previous/next keyframe" should target all layers not just the current GP layer. There can even be an operator that targets this from a custom (ie. hardware buttons in any stylus tablet) shortcut: Insert Blank keyframe (all layers) /// bpy.ops.gpencil.blank_frame_add(all_layers=True)

Philipp Oeser commented

2022-08-19 10:09:03 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-08-19 10:09:03 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2022-08-19 10:09:03 +02:00

Looks like this is something the #grease_pencil and #animation_rigging modules have to discuss/agree upon.

Amélie Fondevilla commented

2022-08-19 10:19:28 +02:00

Yes, I agree.

Also, as I mentionned in the chat, the code makes it look like the intended behavior was to only include animation channels that are selected in the jump :

screen_ops.c:3071 (keyframe_jump_exec)


 if ((scene->flag & SCE_KEYS_NO_SELONLY) == 0) {
    /* Only selected channels are included. */
    ads.filterflag |= ADS_FILTER_ONLYSEL;
  }

When I call 'Jump to next/prev keyframe', flag SCE_KEYS_NO_SELONLY is not set. (meaning the if condition above is true).

However, this is not what's happening (at least for non-grease pencil keyframes)

Yes, I agree. Also, as I mentionned in the chat, the code makes it look like the intended behavior was to only include animation channels that are selected in the jump : screen_ops.c:3071 (keyframe_jump_exec) ``` if ((scene->flag & SCE_KEYS_NO_SELONLY) == 0) { /* Only selected channels are included. */ ads.filterflag |= ADS_FILTER_ONLYSEL; } ``` When I call 'Jump to next/prev keyframe', flag `SCE_KEYS_NO_SELONLY` is **not** set. (meaning the if condition above is true). However, this is not what's happening (at least for non-grease pencil keyframes)

Andy Cuccaro commented

2022-08-19 12:24:49 +02:00

Added subscriber: @AndyCuccaro

Andy Cuccaro commented

2022-08-19 18:50:43 +02:00

I believe that it would actualy make sense if jumping to next keyframe would jump to the next "global" keyframe if there's nothing selected at all, just like within Grease Pencil, if there's no layer selected it then jumps to the next keyframe from that whole GP object.

hamza.SMA commented

2022-08-19 23:38:25 +02:00

Added subscriber: @hamza-el-barmaki

hamza.SMA commented

2022-08-19 23:38:25 +02:00

In #100493#1406211, @AndyCuccaro wrote:
I believe that it would actualy make sense if jumping to next keyframe would jump to the next "global" keyframe if there's nothing selected at all, just like within Grease Pencil, if there's no layer selected it then jumps to the next keyframe from that whole GP object.

as a user of Grease Pencil, i share the same opinion with some addition in summary column
1- clicking in empty place in summary column will diselect all layers so jumping happen for all layer as they are all selected
2- we can use selection box and circle to select a bunch of layers quickly and scrolling automaticaly while selecting layers when using selection box.
3- invert selection (already existe).
......

> In #100493#1406211, @AndyCuccaro wrote: > I believe that it would actualy make sense if jumping to next keyframe would jump to the next "global" keyframe if there's nothing selected at all, just like within Grease Pencil, if there's no layer selected it then jumps to the next keyframe from that whole GP object. as a user of Grease Pencil, i share the same opinion with some addition in summary column 1- clicking in empty place in summary column will diselect all layers so jumping happen for all layer as they are all selected 2- we can use selection box and circle to select a bunch of layers quickly and scrolling automaticaly while selecting layers when using selection box. 3- invert selection (already existe). ......

Daniel Martinez Lara commented

2022-08-21 15:46:59 +02:00

Hi everybody!

The Grease Pencil team we have met to discuss this issue. The current behavior is based on a lot of feedback from productions that are using GP, where it is important to only be able to jump between keyframes on a specific layer.
In an ideal world it would be great if these two behaviors existed by default in Blender. An operator to jump between global frames of the object and another operator to jump only between frames of a selected channel, so it would be consistent.

Apart of this when we have been investigating this matter, we have discovered a small problem related to this when you are in the doopesheet (in Grease pencil submodule)
https://developer.blender.org/T100538

Daniel

Hi everybody! The Grease Pencil team we have met to discuss this issue. The current behavior is based on a lot of feedback from productions that are using GP, where it is important to only be able to jump between keyframes on a specific layer. In an ideal world it would be great if these two behaviors existed by default in Blender. An operator to jump between global frames of the object and another operator to jump only between frames of a selected channel, so it would be consistent. Apart of this when we have been investigating this matter, we have discovered a small problem related to this when you are in the doopesheet (in Grease pencil submodule) https://developer.blender.org/T100538 Daniel

Amélie Fondevilla commented

2022-08-22 09:37:51 +02:00

Okay. I understand, if the behavior is proofed, then it makes sense not to disturb it.
As Andy Cuccaro said, maybe we could add the 'Jump to next keyframe' to be global in the gpencil layers if no layer is selected ?
That would be a way for users to do this global jump, without having to add another operator.

I guess future development of the grease pencil will allow more hybrid 3d/2d projects, so I'm thinking that we should keep in mind this kind of consistency issues.

Okay. I understand, if the behavior is proofed, then it makes sense not to disturb it. As Andy Cuccaro said, maybe we could add the 'Jump to next keyframe' to be global in the gpencil layers if no layer is selected ? That would be a way for users to do this global jump, without having to add another operator. I guess future development of the grease pencil will allow more hybrid 3d/2d projects, so I'm thinking that we should keep in mind this kind of consistency issues.

Philipp Oeser removed the

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Inconsistency in the behavior of 'Jump to next/previous keyframe' operator #100493