Unable to bake UV map

[JWBWork]

Description

Blender 4.1
Dream Textures Windows CUDA 4-1
Windows 11

Cuda version details

> nvcc --version
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2024 NVIDIA Corporation
Built on Wed_Apr_17_19:36:51_Pacific_Daylight_Time_2024
Cuda compilation tools, release 12.5, V12.5.40
Build cuda_12.5.r12.5/compiler.34177558_0

When I try to generate with bake enabled the result uses the original generated image and the baked version of the image is just a black image.

No exceptions/warnings are logged.

Steps to Reproduce

1. Install with blender 4.1
2. Create a mesh
3. Unwrap mesh
4. Duplicate mesh and rotate second mesh 90 degrees
5. Generate with bake enabled using default recommended model

Expected Behavior

I believe the baked image should re-arrange the generated image to match my UV-map.

Addon Version

Windows (CUDA)

Blender Version

Blender 4.1+

GPU

NVIDIA

[ViachaslauBusel]

The same problem. Both on Blender 4.1 and 3.6.

[klfajardo]

Same problem. Blender 4.2

[drvelociraptor]

Same problem here

[drvelociraptor]

did someone find a solution to this?

[Mopzilla]

having this issue, 4.3.1. would love a solution or fix

[jploski]

The reason for the "black image" (Blender 4.2 here) appears to be that the "src" image passed in to the bake function, in script file .config/blender/4.2/scripts/addons/dream_textures/operators/project.py:416 is RGB instead of RGBA - which is expected by the bake function. This can be fixed by replacing the invocation:

                        bake(context, bm, result.image.ravel(), dest, src_uvs, dest_uvs)

with

                        bake(context, bm, image_utils.rgba(result.image).ravel(), dest, src_uvs, dest_uvs)

However, while with this "fix" the image is no longer black, the baking process does not work correctly, i.e. apparently wrong regions of the source image are mapped to the dest UV map.

[jploski]

However, while with this "fix" the image is no longer black, the baking process does not work correctly, i.e. apparently wrong regions of the source image are mapped to the dest UV map.

I had to flip the y coordinate of the src_uv before bake. So in summary this patch solved this issue for me:

diff --git a/operators/project.py b/operators/project.py
index 7180763..c0c8afd 100644
--- a/operators/project.py
+++ b/operators/project.py
@@ -408,8 +408,9 @@ class ProjectDreamTexture(bpy.types.Operator):
                         for face in bm.faces:
                             for loop in face.loops:
                                 src_uvs[loop.vert.index] = loop[src_uv_layer].uv
+                                src_uvs[loop.vert.index][1] = 1.0 - src_uvs[loop.vert.index][1]
                                 dest_uvs[loop.vert.index] = loop[dest_uv_layer].uv
-                        bake(context, bm, result.image.ravel(), dest, src_uvs, dest_uvs)
+                        bake(context, bm, image_utils.rgba(result.image).ravel(), dest, src_uvs, dest_uvs)
                         dest.update()
                         dest.pack()
                         image_texture_node.image = dest

[carson-katri]

@jploski thanks for tracking this down! Would you be able to open a PR with this fix?