Vertex color is interpolated in the 3dview so you end up with a gradient from the colors instead of just flat colors #53316

New Issue

Henrik Berglund · 2017-11-13T21:21:42+01:00

Henrik Berglund commented

2017-11-13 21:21:42 +01:00

System Information
Win 8, GTX1070

Blender Version
Broken: 2.79 official (5bd8ac9) and newer (daily builds).

Short description of error
Vertex color is interpolated in the 3dview so you end up with a gradient from the colors instead of just flat colors. This makes sense if the colors were done on the vertices, but apparently vertex color is now a face thing, so why does the color bleed over other faces?

I attached a picture, the left grid (3x3 face grid) has the face in the middle painted red but the color turns into a gradient when it ideally shouldn't. The right grid has doesn't use vertex colors but instead has two materials, the middle face has a red material and the rest have a blue material applied. These grids should look the same.

Because of this things like ID maps baked from vertex colors don't look as good as they should, you would want the colors to be "vertex accurate" (or in this case "face accurate") but you end up with a lot of unwanted smoothing/interpolation of the colors.

Exact steps for others to reproduce the error

Create a grid with 4/4 subdivisions.
Enter vertex paint mode.
Fill the grid with a color (like blue).
Draw on top of the middle face with another color, like red.
You end up with interpolation between the faces with colors you didn't choose.
Besides, why do you paint on vertices instead of faces if vertex color is now done on faces?
bug_vertex_color_viewinterpolation.blend

**System Information** Win 8, GTX1070 **Blender Version** Broken: 2.79 official (5bd8ac9) and newer (daily builds). **Short description of error** Vertex color is interpolated in the 3dview so you end up with a gradient from the colors instead of just flat colors. This makes sense if the colors were done on the vertices, but apparently vertex color is now a face thing, so why does the color bleed over other faces? I attached a picture, the left grid (3x3 face grid) has the face in the middle painted red but the color turns into a gradient when it ideally shouldn't. The right grid has doesn't use vertex colors but instead has two materials, the middle face has a red material and the rest have a blue material applied. These grids should look the same. ![bug_vertex_color_viewinterpolation.png](https://archive.blender.org/developer/F1132680/bug_vertex_color_viewinterpolation.png) Because of this things like ID maps baked from vertex colors don't look as good as they should, you would want the colors to be "vertex accurate" (or in this case "face accurate") but you end up with a lot of unwanted smoothing/interpolation of the colors. **Exact steps for others to reproduce the error** 1. Create a grid with 4/4 subdivisions. 2. Enter vertex paint mode. 3. Fill the grid with a color (like blue). 4. Draw on top of the middle face with another color, like red. 5. You end up with interpolation between the faces with colors you didn't choose. 6. Besides, why do you paint on vertices instead of faces if vertex color is now done on faces? [bug_vertex_color_viewinterpolation.blend](https://archive.blender.org/developer/F1132688/bug_vertex_color_viewinterpolation.blend)

Henrik Berglund commented

2017-11-13 21:21:42 +01:00

Changed status to: 'Open'

Henrik Berglund commented

2017-11-13 21:21:42 +01:00

Added subscriber: @cyaoeu

Bastien Montagne commented

2017-11-14 11:41:26 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2017-11-14 11:41:26 +01:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2017-11-14 11:41:26 +01:00

Bastien Montagne self-assigned this 2017-11-14 11:41:26 +01:00

Bastien Montagne commented

2017-11-14 11:41:26 +01:00

Thanks for the report, but no bug here, color data might be stored by face-vertex (aka loops), but tools are only designed to work on/with vertices. Doing otherwise would require developping some new tools (like some masking system e.g.).

For now, you can only achieve that kind of effect from code, e.g. to make default cube's first face all red:

mesh = C.object.data
col = mesh.vertex_colors.new()
for l in mesh.polygons.loop_indices:

col.data[l].color = (1.0, 0.0, 0.0, 1.0)

Thanks for the report, but no bug here, color data might be stored by face-vertex (aka loops), but tools are only designed to work on/with vertices. Doing otherwise would require developping some new tools (like some masking system e.g.). For now, you can only achieve that kind of effect from code, e.g. to make default cube's first face all red: ```lang=python mesh = C.object.data col = mesh.vertex_colors.new() for l in mesh.polygons.loop_indices: ``` col.data[l].color = (1.0, 0.0, 0.0, 1.0) ```

Henrik Berglund commented

2017-11-14 13:46:07 +01:00

Thanks for the response. I was actually doing vertex colors using a script but I noticed I was using the "old" method of iterating on vertices, so I changed it to iterate on faces instead (resembling your code) and got more accurate results. :)

Still being able to paint on faces directly without using face selection masking would be nice in the future.

Thanks for the response. I was actually doing vertex colors using a script but I noticed I was using the "old" method of iterating on vertices, so I changed it to iterate on faces instead (resembling your code) and got more accurate results. :) Still being able to paint on faces directly without using face selection masking would be nice in the future.

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Vertex color is interpolated in the 3dview so you end up with a gradient from the colors instead of just flat colors #53316