ID channel AntiAliasing edge artefacts #46751

New Issue

Anna Celarek · 2015-11-12T20:15:40+01:00

Anna Celarek commented

2015-11-12 20:15:40 +01:00

System Information
Windows 10, GTX 950M

Blender Version
Blender 2.76 3bc5399

Short description of error
AntiAliasing option on ID channel causes gap between different ID areas.
The AntiAliasing is not "symmetrical" on the both sides of the border, it eats into the ID area instead of "expanding" some grey value pixels towards the outside.

Exact steps for others to reproduce the error
See the file.
Therea are 2 different material IDs on the cube.
I assign 2 different colors based on ID. The AntiAliasing option causes a white line (from the background color) to appear on the border between the different IDs.

ID_AA.blend

**System Information** Windows 10, GTX 950M **Blender Version** Blender 2.76 3bc5399 **Short description of error** AntiAliasing option on ID channel causes gap between different ID areas. The AntiAliasing is not "symmetrical" on the both sides of the border, it eats into the ID area instead of "expanding" some grey value pixels towards the outside. **Exact steps for others to reproduce the error** See the file. Therea are 2 different material IDs on the cube. I assign 2 different colors based on ID. The AntiAliasing option causes a white line (from the background color) to appear on the border between the different IDs. ![ID_AA.jpg](https://archive.blender.org/developer/F254191/ID_AA.jpg) [ID_AA.blend](https://archive.blender.org/developer/F254193/ID_AA.blend)

Anna Celarek commented

2015-11-12 20:15:40 +01:00

Changed status to: 'Open'

Anna Celarek commented

2015-11-12 20:15:40 +01:00

Added subscriber: @AnnaCelarek

Sergey Sharybin commented

2015-11-13 09:55:33 +01:00

Added subscriber: @Sergey

Sergey Sharybin commented

2015-11-13 09:55:33 +01:00

I don't really see a way to merge images with antialiased mask back together to the same exact combined image, there'll be some extent of "blur" over the edges anyway. However there's a proper point raised that the antialias option is only working in a single direction. Also, adding AA-ed ID masks should in theory give constant 1.0 across full frame i think.

Here's a patch which partially solves the issue D1617. At least it makes edges to be symmetrically darkened and lighetened, but as said even then you can't merge combined image back because of the reason described above.

I don't really see a way to merge images with antialiased mask back together to the same exact combined image, there'll be some extent of "blur" over the edges anyway. However there's a proper point raised that the antialias option is only working in a single direction. Also, adding AA-ed ID masks should in theory give constant 1.0 across full frame i think. Here's a patch which partially solves the issue [D1617](https://archive.blender.org/developer/D1617). At least it makes edges to be symmetrically darkened and lighetened, but as said even then you can't merge combined image back because of the reason described above.

Sergey Sharybin commented

2015-11-13 09:55:45 +01:00

Added subscriber: @ideasman42

Sergey Sharybin commented

2015-11-25 17:20:57 +01:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2015-11-25 17:20:57 +01:00

Sergey Sharybin self-assigned this 2015-11-25 17:20:57 +01:00

Sergey Sharybin commented

2015-11-25 17:20:57 +01:00

Committed D1617 now. This is perhaps as good as we can make AA now. From quick tests masks are now giving constant 1 when adding together, so they're totally symmetrical now. But as was explained above -- merging combined image back from such masks is more tricky and not rea;;y sure if we can really do this.

So thanks for the report, but closing it now!

Committed [D1617](https://archive.blender.org/developer/D1617) now. This is perhaps as good as we can make AA now. From quick tests masks are now giving constant 1 when adding together, so they're totally symmetrical now. But as was explained above -- merging combined image back from such masks is more tricky and not rea;;y sure if we can really do this. So thanks for the report, but closing it now!

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ID channel AntiAliasing edge artefacts #46751