Dynamic Paint doesn't update mesh before 'start frame' #49004

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Cameron Tindall · 2016-08-02T18:00:46+02:00

Cameron Tindall commented

2016-08-02 18:00:46 +02:00

Operating System
Windows 7, gtx 970. Though it happens on all of the machines I have, each have slightly different hardware.
I doubt it's hardware specific, but if it ends up relevant I'll get the system-infos on the machines that reproduce it.

Blender Version
Broken: 2.77a
I haven't known dynamic paint to previously behave differently, it's not a recent change.

Short description of error
When using a vertex-based dynamic paint canvas, the mesh / paint data doesn't update before the start frame. so if an animation has a dynamic paint that doesn't start until mid-way through a scene (to save on baking time, for instance), the painting can be out of sync on any frames before the start frame, the canvas doesn't display the initial state of the paint, it displays the last state that was visible.

This is in contrast to what happens after the end frame, where the canvas will update properly, and any frame past 'end' it will display the state of the paint at the end frame.

It can be 'fixed' by updating the object in some way, the simplest is to select the canvas, press g to move and then cancel with right click, that resets the canvas state to initial. Going into edit mode and then coming back out also works, as well as scrubbing to the start frame of the canvas, then jumping or scrubbing anywhere from there (since now the last visible state is the canvas's initial state).

Exact steps for others to reproduce the error
File : DynPaintUpdateBugTest.blend

The attached file is just a blank file (loaded factory settings) with a subdivided plane using a default dynamic paint canvas, except the start frame is 50 and the end frame is 200. The file then has an icosphere using a default dynamic paint brush, which is animated to move around the canvas a bit, and that's it.

With the attached file (or a similar setup), just press play. Once the animation loops back over to frame 1, it should clearly show the state of the dynamic paint canvas as it was at the end of the animation, during frames 1-49

You can also scrub to somewhere in the middle of the dynamic paint animation, and skip to any frame before frame 50, it shows the last state of the canvas, not an empty canvas.

It's worth noting that this still happens even if the dynamic paint canvas is baked.

This behaviour is mostly a problem when rendering animations out, you have to make sure to be at the scene start, and then use the mode-cancel trick to reset any canvases before pressing the render animation button, or the problem persists into the render.

edit: woops, first bug report, accidentally removed file while writing initial. added back now.

**Operating System** Windows 7, gtx 970. Though it happens on all of the machines I have, each have slightly different hardware. I doubt it's hardware specific, but if it ends up relevant I'll get the system-infos on the machines that reproduce it. **Blender Version** Broken: 2.77a I haven't known dynamic paint to previously behave differently, it's not a recent change. **Short description of error** When using a vertex-based dynamic paint canvas, the mesh / paint data doesn't update before the start frame. so if an animation has a dynamic paint that doesn't start until mid-way through a scene (to save on baking time, for instance), the painting can be out of sync on any frames before the start frame, the canvas doesn't display the initial state of the paint, it displays the last state that was visible. This is in contrast to what happens after the end frame, where the canvas will update properly, and any frame past 'end' it will display the state of the paint at the end frame. It can be 'fixed' by updating the object in some way, the simplest is to select the canvas, press g to move and then cancel with right click, that resets the canvas state to initial. Going into edit mode and then coming back out also works, as well as scrubbing to the start frame of the canvas, then jumping or scrubbing anywhere from there (since now the last visible state is the canvas's initial state). **Exact steps for others to reproduce the error** File : [DynPaintUpdateBugTest.blend](https://archive.blender.org/developer/F331464/DynPaintUpdateBugTest.blend) The attached file is just a blank file (loaded factory settings) with a subdivided plane using a default dynamic paint canvas, except the start frame is 50 and the end frame is 200. The file then has an icosphere using a default dynamic paint brush, which is animated to move around the canvas a bit, and that's it. With the attached file (or a similar setup), just press play. Once the animation loops back over to frame 1, it should clearly show the state of the dynamic paint canvas as it was at the end of the animation, during frames 1-49 You can also scrub to somewhere in the middle of the dynamic paint animation, and skip to any frame before frame 50, it shows the last state of the canvas, not an empty canvas. It's worth noting that this still happens even if the dynamic paint canvas is baked. This behaviour is mostly a problem when rendering animations out, you have to make sure to be at the scene start, and then use the mode-cancel trick to reset any canvases before pressing the render animation button, or the problem persists into the render. edit: woops, first bug report, accidentally removed file while writing initial. added back now.

Cameron Tindall commented

2016-08-02 18:00:46 +02:00

Changed status to: 'Open'

Cameron Tindall commented

2016-08-02 18:00:46 +02:00

Added subscriber: @Antaioz

Bastien Montagne commented

2016-08-05 16:53:28 +02:00

Added subscribers: @miikah, @mont29

Miika Hamalainen was assigned by Bastien Montagne

2016-08-05 16:53:28 +02:00

Bastien Montagne commented

2016-08-05 16:53:28 +02:00

Hrmmmffff… this is half-point cache, half-dynapaint issue…

@miikah P381 fixes the problem, roughly by using more 'virtual local current frame' isntead of scene.cfra, not sure it’s totally OK though?

Don’t quite understand why mem cache is reset on every run too, this kind of defeats the purpose of caching… :/

Hrmmmffff… this is half-point cache, half-dynapaint issue… @miikah [P381](https://archive.blender.org/developer/P381.txt) fixes the problem, roughly by using more 'virtual local current frame' isntead of scene.cfra, not sure it’s totally OK though? Don’t quite understand why mem cache is reset on every run too, this kind of defeats the purpose of caching… :/

blender-admin commented

2016-08-11 12:36:29 +02:00

This issue was referenced by 1fe9d671cf

This issue was referenced by 1fe9d671cf19f339917a78cb3ab0b6148ab1ceff

Alexander Gavrilov commented

2016-08-11 12:37:30 +02:00

Changed status from 'Open' to: 'Resolved'

Alexander Gavrilov closed this issue

2016-08-11 12:37:30 +02:00

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Dynamic Paint doesn't update mesh before 'start frame' #49004