"Allow negative frames" does not allow entering negative start-/end frame #81534

New Issue

Meino Cramer · 2020-10-08T11:09:57+02:00

Meino Cramer commented

2020-10-08 11:09:57 +02:00

System Information
GENTOO Linux (graka-driver:NVIDIA-Linux-x86_64-455.28)
Graphics card:NVIDIA Corporation TU106 [GeForce RTX 2060 SUPER] (rev a1)

Blender Version
Broken: blender-2.91.0-d8fcd8a3162f-linux64 / blender-2.90.1
Worked: not known

Short description of error
Despite "allow negative framer" one cannot enter a negative start-/end frame

Exact steps for others to reproduce the error
Go User Preferences and activate "Allow negative frames"
For the default cube enter keyframes at "-10" and "10".
Accept stripe in the NLA editor
Go to the Timeline
Enter a negative frame number into the "current frame" field: OK
Try the same for the "start frame" or "end frame": Does not work, minimum is "0"
BUT:
Select the NLA stripe
click "Auto set preview range"
Start- and end-frame are set even with negative values.

**System Information** GENTOO Linux (graka-driver:NVIDIA-Linux-x86_64-455.28) Graphics card:NVIDIA Corporation TU106 [GeForce RTX 2060 SUPER] (rev a1) **Blender Version** Broken: blender-2.91.0-d8fcd8a3162f-linux64 / blender-2.90.1 Worked: not known **Short description of error** Despite "allow negative framer" one cannot enter a negative start-/end frame **Exact steps for others to reproduce the error** Go User Preferences and activate "Allow negative frames" For the default cube enter keyframes at "-10" and "10". Accept stripe in the NLA editor Go to the Timeline Enter a negative frame number into the "current frame" field: OK Try the same for the "start frame" or "end frame": Does not work, minimum is "0" BUT: Select the NLA stripe click "Auto set preview range" Start- and end-frame are set even with negative values.

Meino Cramer commented

2020-10-08 11:09:57 +02:00

Added subscriber: @mcq

Philipp Oeser commented

2020-10-08 11:47:23 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2020-10-08 11:47:23 +02:00

Changed status from 'Needs Triage' to: 'Archived'

Philipp Oeser closed this issue

2020-10-08 11:47:23 +02:00

Philipp Oeser self-assigned this 2020-10-08 11:47:23 +02:00

Philipp Oeser commented

2020-10-08 11:47:23 +02:00

The Preview Range is allowed to go into negative range, however the rendering range is not (some rendering formats dont allow for negative frames).

"Auto set preview range" will set Start & End for the Preview Range (and enable it as well), not for the Rendering Range.
These are two different things, toggled by the "Clock" button:

It is a bit of a convoluted workflow, but working as intended atm.
Hope this makes sense? Will close for now (but feel free to comment again if issues persist)

Note: this was even made stricter recently (it was still possible to set the rendering range to negative values using certain operators), see ca38bce46a

The `Preview Range` is allowed to go into negative range, however the rendering range is not (some rendering formats dont allow for negative frames). "Auto set preview range" will set `Start` & `End` for the Preview Range (and enable it as well), not for the Rendering Range. These are two different things, toggled by the "Clock" button: ![image.png](https://archive.blender.org/developer/F8967331/image.png) It is a bit of a convoluted workflow, but working as intended atm. Hope this makes sense? Will close for now (but feel free to comment again if issues persist) Note: this was even made stricter recently (it was still possible to set the rendering range to negative values using certain operators), see ca38bce46a

Meino Cramer commented

2020-10-08 11:58:14 +02:00

I can rendering negative frames when doing as follows:
Select all NLA stripes (includiing those with negative frame counts)
Edit the start frame field by preserving the "-" to a negative frame of your liking
Render Viewport Animation
(using mkv and playing with mpv creates no problems, the frame number display ("i")
also works but count frames starting with 1.)
Rendering with cycles starts with frame 1 and ignores the negative frames though.

I can rendering negative frames when doing as follows: Select all NLA stripes (includiing those with negative frame counts) Edit the start frame field by preserving the "-" to a negative frame of your liking Render Viewport Animation (using mkv and playing with mpv creates no problems, the frame number display ("i") also works but count frames starting with 1.) Rendering with cycles starts with frame 1 and ignores the negative frames though.

Philipp Oeser commented

2020-10-08 13:42:30 +02:00

Added subscribers: @dr.sybren, @brecht

Philipp Oeser commented

2020-10-08 13:42:30 +02:00

In #81534#1030488, @mcq wrote:
I can rendering negative frames when doing as follows:
Select all NLA stripes (includiing those with negative frame counts)
Edit the start frame field by preserving the "-" to a negative frame of your liking
Render Viewport Animation
(using mkv and playing with mpv creates no problems, the frame number display ("i")
also works but count frames starting with 1.)
Rendering with cycles starts with frame 1 and ignores the negative frames though.

Think this already shows that rendering negative frames can be problematic? (assume there are more cases).
That being said, you could still Render Viewport Animation with negative frames, true. (you get those issues you have described)
"Real" rendering [Cyles, Eevee, other rendering engines... will always go from a minimum of 0 as start frame]

Maybe it makes sense to keep the possibility for Render Viewport Animation, as a hidden "last resort" to render negative frames, not sure about this.
I also feel this is a bit of a convoluted workflow, but still, if there are things outside our reach [specific formats] that dont like negative frames, we should not allow for these.

For a final word, maybe @brecht or @dr.sybren can share their views, for now I would say this is all working as expected [and no bug].
If there are bugs with Render Viewport Animation and negative frames, then these could also be reported separately.

> In #81534#1030488, @mcq wrote: > I can rendering negative frames when doing as follows: > Select all NLA stripes (includiing those with negative frame counts) > Edit the start frame field by preserving the "-" to a negative frame of your liking > Render Viewport Animation > (using mkv and playing with mpv creates no problems, the frame number display ("i") > also works but count frames starting with 1.) > Rendering with cycles starts with frame 1 and ignores the negative frames though. Think this already shows that rendering negative frames can be problematic? (assume there are more cases). That being said, you could still `Render Viewport Animation` with negative frames, true. (you get those issues you have described) "Real" rendering [Cyles, Eevee, other rendering engines... will always go from a minimum of 0 as start frame] Maybe it makes sense to keep the possibility for `Render Viewport Animation`, as a hidden "last resort" to render negative frames, not sure about this. I also feel this is a bit of a convoluted workflow, but still, if there are things outside our reach [specific formats] that dont like negative frames, we should not allow for these. For a final word, maybe @brecht or @dr.sybren can share their views, for now I would say this is all working as expected [and no bug]. If there are bugs with `Render Viewport Animation` and negative frames, then these could also be reported separately.

Meino Cramer commented

2020-10-08 17:33:09 +02:00

May be an additonal idea:
I use negative frames as a way to initialize a certain setup to start with "the real animation".
And I see no problem in disabling rendering for negative frames at all -- if it is consistence
throughout blender.
But I would make it more clear to the user GUI-wise:

[current frame] [start frame] [end frame}

will not only confuse me.... ;)

May be an additonal idea: I use negative frames as a way to initialize a certain setup to start with "the real animation". And I see no problem in disabling rendering for negative frames at all -- if it is consistence throughout blender. But I would make it more clear to the user GUI-wise: [current frame] [start frame] [end frame} will not only confuse me.... ;)

Brecht Van Lommel commented

2020-10-12 14:45:58 +02:00

@lichtwerk, I agree that it's not much of an issue if viewport render can still render negative frames.

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"Allow negative frames" does not allow entering negative start-/end frame #81534