Tangent normal map bake has irregular values #114111

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opened 2023-10-24 17:04:16 +02:00 by Zak-Nelson · 3 comments

Zak-Nelson commented

2023-10-24 17:04:16 +02:00

System Information
Operating system: Windows 11
Graphics card: NVIDIA GeForce RTX 4080 Laptop GPU

Blender Version
Broken: 3.6.4, 2.79
Worked: None tested

Short description of error
Normal texture bake appears to be baking the difference of the object without custom normals to the object with custom normals. This object has gone through joining of other objects with custom normals, sometimes with weighted normal modifier applied, sometimes using bpy.ops.mesh.customdata_custom_splitnormals_add()

Exact steps for others to reproduce the error
See blend file setup and screenshot of file below and click bake.

**System Information** Operating system: Windows 11 Graphics card: NVIDIA GeForce RTX 4080 Laptop GPU **Blender Version** Broken: 3.6.4, 2.79 Worked: None tested **Short description of error** Normal texture bake appears to be baking the difference of the object without custom normals to the object with custom normals. This object has gone through joining of other objects with custom normals, sometimes with weighted normal modifier applied, sometimes using bpy.ops.mesh.customdata_custom_splitnormals_add() ![image](/attachments/dfe9ee5d-49a6-4a7b-b9be-44acf5fc4a6b) **Exact steps for others to reproduce the error** See blend file setup and screenshot of file below and click bake.

616 KiB

custom_normal_bake_example.blend

1.1 MiB

Zak-Nelson added the

labels 2023-10-24 17:04:17 +02:00

Iliya Katushenock added the

Render & Cycles

Render Pipeline

labels 2023-10-24 17:08:39 +02:00

Germano Cavalcante commented

2023-10-25 16:23:05 +02:00

Member

It doesn't seem to be "based on the mesh normals without custom normals", otherwise, if we remove the custom normals the result should be the same, no?

But I can confirm that the resulting normal map is strange. (I just don't know exactly what's going on).

It doesn't seem to be "based on the mesh normals without custom normals", otherwise, if we remove the custom normals the result should be the same, no? But I can confirm that the resulting normal map is strange. (I just don't know exactly what's going on).

Germano Cavalcante added

Render & Cycles

and removed

Render & Cycles

labels 2023-10-25 16:23:24 +02:00

Zak-Nelson changed title from ~~Tangent normal map bake not based on custom normals~~ to Tangent normal map bake has irregular values

2023-10-25 17:47:59 +02:00

Zak-Nelson commented

2023-10-25 17:51:41 +02:00

Author

I've updated the title and description to more accurately describe the issue.

I've updated the title and description to more accurately describe the issue.

Zak-Nelson commented

2023-10-25 21:57:17 +02:00

Author

This type of issue seems to be caused when joining a mesh type object without any mesh data, but is still allowed to have split custom normal data saved. The following script shows the steps for recreating the issue and can be run with this accompanying .Blend file below. If you remove everything before the line "# create object with no geometry" the bake is correct, but without removing that section, you will get the error presented.

import bpy
def duplicate_active_and_join_to_empty():
    new_obj_name='Applied Modifiers and joined to empty'
    new_obj=bpy.data.objects.get(new_obj_name)
    if new_obj is not None:
        bpy.data.objects.remove(new_obj)
    obj=bpy.context.active_object
    if obj is None:
        print('Select an active object')
        return
    #Duplicate the original object
    duplicate = obj.copy()
    duplicate.data = duplicate.data.copy()
    duplicate.name = f'~{obj.name}'
    duplicate.matrix_world = obj.matrix_world
    bpy.context.scene.collection.objects.link(duplicate)
    duplicate.location.x=2
    obj.select_set(False)
    duplicate.select_set(True)
    bpy.context.view_layer.objects.active = duplicate
    duplicate.data.use_auto_smooth=True
    bpy.ops.object.convert(target='MESH')
    bpy.ops.mesh.customdata_custom_splitnormals_add()

    # create object with no geometry
    empty_mesh = bpy.data.meshes.new(new_obj_name)
    empty_mesh = bpy.data.objects.new(new_obj_name, empty_mesh)
    bpy.context.scene.collection.objects.link(empty_mesh)
    empty_mesh.location = (0, 0, 0)

    # Create empty object to join geometry to
    empty_mesh.select_set(True)
    empty_mesh.data.use_auto_smooth=True
    bpy.context.view_layer.objects.active = empty_mesh
    bpy.ops.mesh.customdata_custom_splitnormals_add()
    bpy.ops.object.join()
    bpy.context.scene.render.engine = 'CYCLES'
    bpy.ops.object.bake(type='NORMAL')
    bpy.context.view_layer.objects.active = obj
duplicate_active_and_join_to_empty()

This type of issue seems to be caused when joining a mesh type object without any mesh data, but is still allowed to have split custom normal data saved. The following script shows the steps for recreating the issue and can be run with this accompanying .Blend file below. If you remove everything before the line "# create object with no geometry" the bake is correct, but without removing that section, you will get the error presented. ``` import bpy def duplicate_active_and_join_to_empty(): new_obj_name='Applied Modifiers and joined to empty' new_obj=bpy.data.objects.get(new_obj_name) if new_obj is not None: bpy.data.objects.remove(new_obj) obj=bpy.context.active_object if obj is None: print('Select an active object') return #Duplicate the original object duplicate = obj.copy() duplicate.data = duplicate.data.copy() duplicate.name = f'~{obj.name}' duplicate.matrix_world = obj.matrix_world bpy.context.scene.collection.objects.link(duplicate) duplicate.location.x=2 obj.select_set(False) duplicate.select_set(True) bpy.context.view_layer.objects.active = duplicate duplicate.data.use_auto_smooth=True bpy.ops.object.convert(target='MESH') bpy.ops.mesh.customdata_custom_splitnormals_add() # create object with no geometry empty_mesh = bpy.data.meshes.new(new_obj_name) empty_mesh = bpy.data.objects.new(new_obj_name, empty_mesh) bpy.context.scene.collection.objects.link(empty_mesh) empty_mesh.location = (0, 0, 0) # Create empty object to join geometry to empty_mesh.select_set(True) empty_mesh.data.use_auto_smooth=True bpy.context.view_layer.objects.active = empty_mesh bpy.ops.mesh.customdata_custom_splitnormals_add() bpy.ops.object.join() bpy.context.scene.render.engine = 'CYCLES' bpy.ops.object.bake(type='NORMAL') bpy.context.view_layer.objects.active = obj duplicate_active_and_join_to_empty() ```

issue_114111.blend

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