map UV node produces image artifacts #45617

New Issue

Daniel Widmann · 2015-07-30T11:00:04+02:00

Daniel Widmann commented

2015-07-30 11:00:04 +02:00

System Information
Windows 7 Professional Service Pack 1
NVIDIA GeForce GTX 660

Blender Version
Broken: 2.75a c27589e

Short description of error
Using the map uv node in the compositor produces image artifacts. The uploaded images show one example image input, an example uv map and the result. The uv map is smooth and has no jumps, but the edges of the square in the output image look jagged. Also note that the output should not show the white line around the circle because there actually is a sudden change to black in the uv map. My guess is that there could be something wrong with the image coordinates used to access the uv map and/or the pixel weights used for filtering when applying the uv map.

Exact steps for others to reproduce the error
Attached is a simple blend file that renders a white square in low resolution and some linear texture coordinates that should not change the image when used as a uv map (though they change it a little). The composite node also adds a small offset to the uv map over time. So when stepping forward frame by frame the white square will slowly move; However, every two pixels it moves, it seems to jump back one pixel.
map_uv_bug.blend

**System Information** Windows 7 Professional Service Pack 1 NVIDIA GeForce GTX 660 **Blender Version** Broken: 2.75a c27589e **Short description of error** Using the map uv node in the compositor produces image artifacts. The uploaded images show one example image input, an example uv map and the result. The uv map is smooth and has no jumps, but the edges of the square in the output image look jagged. Also note that the output should not show the white line around the circle because there actually is a sudden change to black in the uv map. My guess is that there could be something wrong with the image coordinates used to access the uv map and/or the pixel weights used for filtering when applying the uv map. ![Example_Image_Input.png](https://archive.blender.org/developer/F216054/Example_Image_Input.png) ![Example_UV_Input.png](https://archive.blender.org/developer/F216056/Example_UV_Input.png) ![Example_Output.png](https://archive.blender.org/developer/F216058/Example_Output.png) **Exact steps for others to reproduce the error** Attached is a simple blend file that renders a white square in low resolution and some linear texture coordinates that should not change the image when used as a uv map (though they change it a little). The composite node also adds a small offset to the uv map over time. So when stepping forward frame by frame the white square will slowly move; However, every two pixels it moves, it seems to jump back one pixel. [map_uv_bug.blend](https://archive.blender.org/developer/F216053/map_uv_bug.blend)

Daniel Widmann commented

2015-07-30 11:00:04 +02:00

Changed status to: 'Open'

Daniel Widmann commented

2015-07-30 11:00:04 +02:00

Added subscriber: @nion

khaled commented

2015-07-30 12:09:28 +02:00

Added subscriber: @KhaledAbdi

Sergey Sharybin commented

2015-08-04 12:15:01 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2015-08-04 12:15:01 +02:00

This actually seems quite the same as #42844, but needs some further investigation.

blender-admin commented

2015-08-27 18:50:40 +02:00

This issue was referenced by 3ec81b814c

This issue was referenced by 3ec81b814c995b585f19c97cf87fee5b7195382b

Sergey Sharybin commented

2015-08-27 19:00:31 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2015-08-27 19:00:31 +02:00

Daniel Widmann commented

2015-09-02 17:00:19 +02:00

Changed status from 'Resolved' to: 'Open'

Daniel Widmann reopened this issue

2015-09-02 17:00:19 +02:00

Daniel Widmann commented

2015-09-02 17:00:19 +02:00

I took todays dailys build (Date: 2015-09-02 03:41 Hash: f6e0262) and tested it. I made some tests with one fixed uv coordinate for the whole image and some tests with linear, "undistorted" uv maps and got the results I would expect. With other UV Maps, however, there still seems to be something off. See the strange checker like pattern on this bush after applying a uv map to the image:

Edit: Note that the left side is only a zoomed in image of the right side and not the application of the uv map. The UV map has already been applied on the right side.

I have made a .blend file to reproduce this effect. There is also a text object with instructions included in the blend file:

map_uv_bug2.blend

This might also be caused by the EWA Filter itself rather than the MAP UV node.

I took todays dailys build (Date: 2015-09-02 03:41 Hash: f6e0262) and tested it. I made some tests with one fixed uv coordinate for the whole image and some tests with linear, "undistorted" uv maps and got the results I would expect. With other UV Maps, however, there still seems to be something off. See the strange checker like pattern on this bush after applying a uv map to the image: ![checkerArtifacts.png](https://archive.blender.org/developer/F229914/checkerArtifacts.png) *Edit: Note that the left side is only a zoomed in image of the right side and not the application of the uv map. The UV map has already been applied on the right side.* I have made a .blend file to reproduce this effect. There is also a text object with instructions included in the blend file: [map_uv_bug2.blend](https://archive.blender.org/developer/F229916/map_uv_bug2.blend) This might also be caused by the EWA Filter itself rather than the MAP UV node.

Sergey Sharybin commented

2015-09-02 17:51:35 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2015-09-02 17:51:35 +02:00

Sergey Sharybin self-assigned this 2015-09-02 17:51:35 +02:00

Sergey Sharybin commented

2015-09-02 17:51:35 +02:00

Please don't report old reports with new issues, submit a new report instead.

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map UV node produces image artifacts #45617