Grease Pencil Overlap problem #59543

New Issue

Tom Nelson · 2018-12-18T09:23:56+01:00

Tom Nelson commented

2018-12-18 09:23:56 +01:00

Operating system: Windows 10 b17763.134
Graphics card: AMD Vega 64 (Strix)

Broken: 2.80, 9149e89421, 2018-12-16

When applying a grease pencil visual effect, the grease pencil object loses the effect when overlapping another grease pencil opject.

In this example I have a GP rain layer with a blur, when the rain overlaps another GP object in the background the place where it overlaps loses the blur effect in the final render.

I've opened the file in multiple builds with the same effect.

Pic attached.

Operating system: Windows 10 b17763.134 Graphics card: AMD Vega 64 (Strix) Broken: 2.80, 9149e894210, 2018-12-16 When applying a grease pencil visual effect, the grease pencil object loses the effect when overlapping another grease pencil opject. In this example I have a GP rain layer with a blur, when the rain overlaps another GP object in the background the place where it overlaps loses the blur effect in the final render. I've opened the file in multiple builds with the same effect. Pic attached. ![GP_overlap_problem.png](https://archive.blender.org/developer/F5990757/GP_overlap_problem.png)

Tom Nelson commented

2018-12-18 09:23:56 +01:00

Added subscriber: @tomnel

William Reynish commented

2018-12-18 09:47:57 +01:00

Added subscriber: @WilliamReynish

William Reynish commented

2018-12-18 09:47:57 +01:00

Can you make a simple blend file that demonstrates this issue?

Tom Nelson commented

2018-12-18 10:25:08 +01:00

I made a simple blend file but the behavior is a little different, the white foreground GPlines dissappear when over a dark BG GP object and a blur visual effect applied.

GP_overlay_problem.blend

I made a simple blend file but the behavior is a little different, the white foreground GPlines dissappear when over a dark BG GP object and a blur visual effect applied. [GP_overlay_problem.blend](https://archive.blender.org/developer/F5991248/GP_overlay_problem.blend)

Tom Nelson commented

2018-12-18 10:27:38 +01:00

If you look at it from the side you can see the white lines that are not affected by the blur effect a little bit.

Also I opened my main problem blend file on an nvidia 1080 windows 10 machine and the problem exists there too.

If you look at it from the side you can see the white lines that are not affected by the blur effect a little bit. Also I opened my main problem blend file on an nvidia 1080 windows 10 machine and the problem exists there too.

Antonio Vazquez commented

2018-12-18 10:27:39 +01:00

Added subscriber: @antoniov

Antonio Vazquez commented

2018-12-18 10:27:39 +01:00

This comment was removed by @antoniov

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Antonio Vazquez commented

2018-12-18 10:50:08 +01:00

I have tested and the blur works with overlap objects. We need a simple file to reproduce the problem or to verify if this is a technical limitation.

Anyway, I think this is related to #59425.

I have tested and the blur works with overlap objects. We need a simple file to reproduce the problem or to verify if this is a technical limitation. Anyway, I think this is related to #59425.

Antonio Vazquez commented

2018-12-18 10:55:54 +01:00

@tomnel Anyway, while we fix the z-depth problem (#59425), you can fix it separating the rain in a new GP object and verifying the rain origin is in front of other objects origin (it's the same where are the strokes, the important is where is the origin).

Tom Nelson commented

2018-12-18 17:57:47 +01:00

Thanks Antonio,
There is a simple blend file attached above. In it there are two GP objects, a black circle and in front of the circle a bunch of white lines with a blur effect.
For me the white lines disappear or lose the blur effect when in front of the dark circle GP object.
That doesn’t show up for you?

I will check again but I believe the origin of the lines is in front of the dark circle.

Thanks Antonio, There is a simple blend file attached above. In it there are two GP objects, a black circle and in front of the circle a bunch of white lines with a blur effect. For me the white lines disappear or lose the blur effect when in front of the dark circle GP object. That doesn’t show up for you? I will check again but I believe the origin of the lines is in front of the dark circle.

Antonio Vazquez commented

2018-12-18 19:50:23 +01:00

@tomnel I see now the problem, it looks the z-depth is not working as expected when apply blur.

Antonio Vazquez commented

2018-12-18 19:54:21 +01:00

@tomnel Try to change the depth ordering of the rain to Front.

I need investigate about this, it looks a precision problem when use blur because the blured areas are too "low" values and the code is clipping it.

@tomnel Try to change the depth ordering of the rain to Front. ![image.png](https://archive.blender.org/developer/F5995521/image.png) I need investigate about this, it looks a precision problem when use blur because the blured areas are too "low" values and the code is clipping it.

Tom Nelson commented

2018-12-18 21:33:18 +01:00

This comment was removed by @tomnel

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Tom Nelson commented

2018-12-18 21:34:42 +01:00

Setting the depth ordering worked for the viewport (thanks!), but not the render output.
Taking a close look at the render it looks like the blur is ok but the opacity is not so where the rain overlays another GP object the opacity jumps to 100%

I am using a GP modifier to lower the opacity

Setting the depth ordering worked for the viewport (thanks!), but not the render output. Taking a close look at the render it looks like the blur is ok but the opacity is not so where the rain overlays another GP object the opacity jumps to 100%![OV.png](https://archive.blender.org/developer/F5996705/OV.png) I am using a GP modifier to lower the opacity

Antonio Vazquez commented

2018-12-18 23:01:06 +01:00

I have done some changes in 0d7fe55d0e commit. You don't need put in Front.

Still need to improve render.

I have done some changes in 0d7fe55d0e76 commit. You don't need put in Front. Still need to improve render.

Antonio Vazquez self-assigned this 2018-12-18 23:01:39 +01:00

Tom Nelson commented

2019-02-07 07:36:22 +01:00

Can confirm, working in viewport, not in render. thanks!