GPv3: Natural Drawing build modifier can not be slowed down on premade objects #130201

New Issue

Alaska · 2024-11-13T04:22:20+01:00

Alaska commented

2024-11-13 04:22:20 +01:00

System Information
Operating system: Windows-10-10.0.22631-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 565.90 Opengl Backend

Blender Version
Broken: version: 4.3.0 Beta, branch: blender-v4.3-release, commit date: 2024-11-12 23:05, hash: baa193c3b6c9
Worked: 4.2

Short description of error
When a premade grease pencil object (E.g. Built in monkey head) has the build modifier added to it, and set to Natural Drawing mode, the build modifier can not be slowed down.

Everything works fine for hand drawn strokes.

Exact steps for others to reproduce the error

Add a Grease Pencil monkey to the scene
Give it a Build modifier
Change the Build modifer Timing to Natural Drawing Speed
Play back the animation and take note of how long it takes to complete.
Reduce the Speed factor in the build modifier to something small (E.g. 0.05) and increase the Maximum gap in neccesary.
Play back the animation and notice it still takes the same amount of time to complete.
Compare to a manually drawn grease pencil stroke, or 4.2 and notice it works for those.

**System Information** Operating system: Windows-10-10.0.22631-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 565.90 Opengl Backend **Blender Version** Broken: version: 4.3.0 Beta, branch: blender-v4.3-release, commit date: 2024-11-12 23:05, hash: `baa193c3b6c9` Worked: 4.2 **Short description of error** When a premade grease pencil object (E.g. Built in monkey head) has the build modifier added to it, and set to `Natural Drawing` mode, the build modifier can not be slowed down. Everything works fine for hand drawn strokes. **Exact steps for others to reproduce the error** - Add a Grease Pencil monkey to the scene - Give it a `Build` modifier - Change the Build modifer `Timing` to `Natural Drawing Speed` - Play back the animation and take note of how long it takes to complete. - Reduce the `Speed factor` in the build modifier to something small (E.g. 0.05) and increase the `Maximum gap` in neccesary. - Play back the animation and notice it still takes the same amount of time to complete. - Compare to a manually drawn grease pencil stroke, or 4.2 and notice it works for those.

Alaska added the

labels 2024-11-13 04:22:20 +01:00

Alaska commented

2024-11-13 04:22:43 +01:00

This is a minor issue and can probably be left for 4.3.1 or 4.4

YimingWu commented

2024-11-13 04:34:14 +01:00

Humm this is interesting. Not sure why, maybe it doesn't have enough stroke strart/gap information...?

Is this with #130199 or not?

Humm this is interesting. Not sure why, maybe it doesn't have enough stroke strart/gap information...? Is this with #130199 or not?

Alaska commented

2024-11-13 04:46:49 +01:00

Humm this is interesting. Not sure why, maybe it doesn't have enough stroke strart/gap information...?

Premade curves don't have a detla_time attribute which is neccesary for the Natural Drawing mode.

So it falls back to a different mode which doesn't take the settings of the Natural drawing mode into account.

See 01db47b82c (Fixes: #129766)

Is this with #130199 or not?

I can reproduce it in the release branch, so it's related (as it's the Natural Drawing speed), but needs a seperate fix.

> Humm this is interesting. Not sure why, maybe it doesn't have enough stroke strart/gap information...? Premade curves don't have a detla_time attribute which is neccesary for the `Natural Drawing` mode. So it falls back to a different mode which doesn't take the settings of the `Natural drawing` mode into account. See 01db47b82c77610780159d543227e5e082a55071 (Fixes: #129766) > Is this with #130199 or not? I can reproduce it in the release branch, so it's related (as it's the Natural Drawing speed), but needs a seperate fix.

Pratik Borhade commented

2024-11-13 10:16:03 +01:00

Hi, can confirm

Pratik Borhade added

and removed

labels 2024-11-13 10:16:24 +01:00

Pratik Borhade added this to the 4.3 milestone 2024-11-13 10:16:37 +01:00

Hans Goudey changed title from ~~Grease Pencil Natural Drawing build modifier can not be slowed down on premade Grease Pencil objects~~ to GPv3: Natural Drawing build modifier can not be slowed down on premade Grease Pencil objects

2024-11-13 14:50:25 +01:00

Hans Goudey changed title from ~~GPv3: Natural Drawing build modifier can not be slowed down on premade Grease Pencil objects~~ to GPv3: Natural Drawing build modifier can not be slowed down on premade objects

2024-11-13 14:54:09 +01:00

Hans Goudey commented

2024-11-13 15:17:54 +01:00

Seems like there should be fallback behavior that respects the speed factor when the delta time attribute is missing.

Falk David commented

2024-11-15 11:11:43 +01:00

Since this is not a critical issue, I'll remove the 4.3 target.

Falk David removed this from the 4.3 milestone 2024-11-15 11:11:49 +01:00

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GPv3: Natural Drawing build modifier can not be slowed down on premade objects #130201