GPencil: Add Holdout material option to open holes in filled areas #79878

New Issue

Antonio Vazquez · 2020-08-18T12:30:30+02:00

Antonio Vazquez commented

2020-08-18 12:30:30 +02:00

Add an option to materials to be used as a masking. Any stroke that uses this material, will remove any stroke below and it will make it transparent. This is useful to open holes in filled areas.

This is a prerequisite for #79877

Add an option to materials to be used as a masking. Any stroke that uses this material, will remove any stroke below and it will make it transparent. This is useful to open holes in filled areas. This is a prerequisite for #79877

Antonio Vazquez self-assigned this 2020-08-18 12:30:30 +02:00

Antonio Vazquez commented

2020-08-18 12:30:30 +02:00

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

Antonio Vazquez commented

2020-08-18 12:30:30 +02:00

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

Antonio Vazquez commented

2020-08-18 16:30:53 +02:00

2020-07-21 11-33-57.mp4

[2020-07-21 11-33-57.mp4](https://archive.blender.org/developer/F8791132/2020-07-21_11-33-57.mp4)

Antonio Vazquez changed title from ~~GPencil: Add masking material option to open holes in filled areas~~ to GPencil: Add Holdout material option to open holes in filled areas

2020-09-17 19:47:25 +02:00

blender-admin commented

2020-09-18 18:23:25 +02:00

This issue was referenced by 0335c1fd21

This issue was referenced by 0335c1fd21dd49906968a2aa85b0016c8047f695

Antonio Vazquez commented

2020-09-18 18:29:22 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Antonio Vazquez closed this issue

2020-09-18 18:29:22 +02:00

Antonio Vazquez commented

2020-09-18 18:29:22 +02:00

Done in 0335c1fd21

Done in 0335c1fd21dd

cadtofu commented

2020-09-28 19:11:50 +02:00

Added subscribers: @Antonio-29, @cadtofu

cadtofu commented

2020-09-28 19:11:50 +02:00

@antoniov Thank you a lot for a direct svg to gp importer. I tested it a lot these days.
It is great convinience to import svg assets into archviz scene now. Even the svg layers can be correctly imported as gp layers.
The main limitation I encountered is that hollow shape (ie, compound path made with boolean difference in Inkscape) cannot be implemented in grease pencil. I already see layer mask of grease pencil as your effort to solve this issue, but each hollow shape must be separated into 2 layers first which would make layer management a little tedious IMHO. So, I would rather like this new "Holdout material" a better solution for this issue, if only one separated layer works well.
For now, the holdout material can only affect whole GP object,. Could I suggest you add an option so that holdout only affect also a single GP layer. I believe this will add more use cases for it.
Below is my screenshot and mock-up UI suggestion. My intent is that glasses lenses should affect glasses frame, but donnot affect human face.

Please tell your considerations, thanks again.

Also the source svg file and object blend file if useful.

3_bld_gp-material-holdout.zip

@antoniov Thank you a lot for a direct svg to gp importer. I tested it a lot these days. It is great convinience to import svg assets into archviz scene now. Even the svg layers can be correctly imported as gp layers. The main limitation I encountered is that hollow shape (ie, compound path made with boolean difference in Inkscape) cannot be implemented in grease pencil. I already see layer mask of grease pencil as your effort to solve this issue, but each hollow shape must be separated into 2 layers first which would make layer management a little tedious IMHO. So, I would rather like this new "Holdout material" a better solution for this issue, if only one separated layer works well. For now, the holdout material can only affect whole GP object,. Could I suggest you add an option so that holdout only affect also a single GP layer. I believe this will add more use cases for it. Below is my screenshot and mock-up UI suggestion. My intent is that glasses lenses should affect glasses frame, but donnot affect human face. ![0_org-inkscape_g.jpg](https://archive.blender.org/developer/F8932579/0_org-inkscape_g.jpg) ![2_gp-material-holdou_g.jpg](https://archive.blender.org/developer/F8932583/2_gp-material-holdou_g.jpg) ![9_fake-ui_g.jpg](https://archive.blender.org/developer/F8932585/9_fake-ui_g.jpg) Please tell your considerations, thanks again. Also the source svg file and object blend file if useful. ![0_glassesman.svg](https://archive.blender.org/developer/F8932599/0_glassesman.svg) [3_bld_gp-material-holdout.zip](https://archive.blender.org/developer/F8932617/3_bld_gp-material-holdout.zip)

cadtofu commented

2020-10-10 17:38:36 +02:00

In #79878#1018717, @antoniov wrote:
Done in 0335c1fd21

Hi, please take a look at my above suggestion. Thanks.

> In #79878#1018717, @antoniov wrote: > Done in 0335c1fd21dd Hi, please take a look at my above suggestion. Thanks.

Antonio Vazquez commented

2020-10-10 18:45:53 +02:00

@cadtofu Your request is not as easy as it looks. The holdout is done at the pixel level in the shader and there isn't any layer data at that level. To do what you want, we would have to render layer by layer and this would be very slow, so it's not a solution.

cadtofu commented

2020-10-11 20:19:59 +02:00

In #79878#1031730, @antoniov wrote:
@cadtofu Your request is not as easy as it looks. The holdout is done at the pixel level in the shader and there isn't any layer data at that level. To do what you want, we would have to render layer by layer and this would be very slow, so it's not a solution.

Thanks for your feedback. Then I will go on using gp layer mask as solution.

As for the SVG importer, I think this is a limitation, that doesnot support complex shpae such as hollow, clip and mask.

After all, SVG and GP are quite different data structures.

> In #79878#1031730, @antoniov wrote: > @cadtofu Your request is not as easy as it looks. The holdout is done at the pixel level in the shader and there isn't any layer data at that level. To do what you want, we would have to render layer by layer and this would be very slow, so it's not a solution. Thanks for your feedback. Then I will go on using gp layer mask as solution. As for the SVG importer, I think this is a limitation, that doesnot support complex shpae such as hollow, clip and mask. After all, SVG and GP are quite different data structures.

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GPencil: Add Holdout material option to open holes in filled areas #79878