Texture paint - sample color picker is highly unreliable when "clip end" distances are large enough #72372

New Issue

Vas · 2019-12-12T03:46:47+01:00

Vas commented

2019-12-12 03:46:47 +01:00

System Information
Operating system: Windows-10-10.0.17763-SP0 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.66

Blender Version
Broken: version: 2.82 (sub 4), branch: master, commit date: 2019-12-10 23:56, hash: 63d521432e
Worked: (optional)

Short description of error
I'm not sure if this is a bug or a system limitation, but after couple of hours prodding I can conclude this:

If clip end is 100m-1000m and camera lens is <100mm , Texture paint sample color is accuare and reliable
If clip end is 1000m-6000m and camera lens is 35-200mm, when you zoom in and start sampling color, there's a small chance of wrong color picking (sampling merged colors instead of original texture source)
if clip end is >10000m and there's any kind of zoom in, the color picking becomes 50/50 chance to actually sample the texture source, basically impossible to pick the right color

This can be a pretty big issue for someone who works on big scenes and paints textures (like roughness maps/normal maps) in blender, You naturally tend to zoom in a lot to have a better stroke/precision, but zooming in viewport causes a huge decreasce in sampling accuracy. I found out the cause and managed to metigate it by decreascing Clip End distance of some cameras. And in the example below, 1000m is not even that much for a clip end distance.

Here's a clip demonstrating what I mean:
2019-12-12 02-01-48.mp4

In the source file I demonstrated the minumum clip end + viewport zoom necessary to casue this instability, the main culprid of this is the Clip End + Viewport zoom in values. If Clip End is anything like 10000m then it becomes practically unusable to sample colors

Also this effect is a lot more proiminent on the edges of the mesh

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]

Open the blend file
Enable the Render view
make sure the cyan texture is selected in shader editor (bad big.png)
Enter the camera view
go to 3D view and enter the Texture Paint mode
Press S to sample the colors (less reliable on edges of mesh
Zoom in and notice that sampling becomes even less accurate

sample color bug 2.blend

**System Information** Operating system: Windows-10-10.0.17763-SP0 64 Bits Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.66 **Blender Version** Broken: version: 2.82 (sub 4), branch: master, commit date: 2019-12-10 23:56, hash: `63d521432e` Worked: (optional) **Short description of error** I'm not sure if this is a bug or a system limitation, but after couple of hours prodding I can conclude this: - If clip end is 100m-1000m and camera lens is <100mm , Texture paint sample color is accuare and reliable - If clip end is 1000m-6000m and camera lens is 35-200mm, when you zoom in and start sampling color, there's a small chance of wrong color picking (sampling merged colors instead of original texture source) - if clip end is >10000m and there's any kind of zoom in, the color picking becomes 50/50 chance to actually sample the texture source, basically impossible to pick the right color This can be a pretty big issue for someone who works on big scenes and paints textures (like roughness maps/normal maps) in blender, You naturally tend to zoom in a lot to have a better stroke/precision, but zooming in viewport causes a huge decreasce in sampling accuracy. I found out the cause and managed to metigate it by decreascing Clip End distance of some cameras. And in the example below, 1000m is not even that much for a clip end distance. Here's a clip demonstrating what I mean: [2019-12-12 02-01-48.mp4](https://archive.blender.org/developer/F8210974/2019-12-12_02-01-48.mp4) In the source file I demonstrated the minumum clip end + viewport zoom necessary to casue this instability, the main culprid of this is the Clip End + Viewport zoom in values. If Clip End is anything like 10000m then it becomes practically unusable to sample colors Also this effect is a lot more proiminent on the edges of the mesh **Exact steps for others to reproduce the error** [Please describe the exact steps needed to reproduce the issue] - Open the blend file - Enable the Render view - make sure the cyan texture is selected in shader editor (bad big.png) - Enter the camera view - go to 3D view and enter the Texture Paint mode - Press S to sample the colors (less reliable on edges of mesh - Zoom in and notice that sampling becomes even less accurate [sample color bug 2.blend](https://archive.blender.org/developer/F8211013/sample_color_bug_2.blend)

Vas commented

2019-12-12 03:46:47 +01:00

Added subscriber: @Alumx

Germano Cavalcante commented

2019-12-16 12:46:42 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2019-12-16 12:46:42 +01:00

Dev note:
I suspect this is a raycast inaccuracy due to the distance from ray_start.
If so, a solution would be to move ray_start to the point where it hits bound_box.

Dev note: I suspect this is a raycast inaccuracy due to the distance from ray_start. If so, a solution would be to move ray_start to the point where it hits bound_box.

Germano Cavalcante self-assigned this 2019-12-17 19:06:48 +01:00

Germano Cavalcante commented

2019-12-17 19:06:48 +01:00

After investigating, I realized that it has nothing to do with raycast, but with select_engine.

blender-admin commented

2019-12-18 13:41:03 +01:00

This issue was referenced by 61f4a7d1f5

This issue was referenced by 61f4a7d1f593e3870e7a0df4b32e95516b236eef

Germano Cavalcante commented

2019-12-18 13:41:35 +01:00

Changed status from 'Open' to: 'Resolved'

Germano Cavalcante closed this issue

2019-12-18 13:41:35 +01:00

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Texture paint - sample color picker is highly unreliable when "clip end" distances are large enough #72372