outline.txt

TODO:
WE NEED AN IMPORTER THAT WILL BRING IN THE BAKED MATERIALS (?)
the OBJECT needs uvs but the TEXTURE MAPPING doesnt! You can have projections set to OBJECT! (https://youtu.be/Se8GdHptD4A?si=MC6_EaKap7caN-EN&t=548)
(to be imported as a static mesh, and the materials need to be imported as material instances ???)
make render samples set to 10 - fast bake, same quality. ask user to use CPU or GPU compute
if there is  metalness the bake may be all black
make color space noncolor EXCEPT for diffuse
use emit on bake
WILL I NEED TO USE NORMAL SPACE FOR THE NORMAL MAP?

A Blender script to export materials and lights for use in an alternative 3D software.
This specific use case is for Blender to Unreal Engine.

USE:
The Blender lookdev artists need a process for transferring their fine-tuned set designs from Blender to Unreal.

WHY:
Different 3D programs do not transfer similar 3D assets as 1:1 objects.
For example, a light exported from Blender with specific attributes set will not light the same exact scene the same way in Maya.
These programs have different architecture underneath the hood that inform how the scene is displayed.
There are solutions actively being produced to mitigate this issue, such as USD, there is still no one size fits all fix. 

SOLUTION:
A tool that will allow for different assets to be exported from Blender in a manner best suited for use in Unreal.
________________________________________________________________________________________________________________________


The tool will export 3 types of assets:
1. Materials
2. Lights
3. Geometry

The 3 export types will be in separate files, but they will all be in the same project folder structure.


________________________________________
THE 3 ASSETS:
________________________________________

MATERIALS
When our artists lookdev, they are editing the materials via Blender's shader network system.
To re-create this in Unreal would be a nightmare, as re-creating the same shader network would be duplicative work,
but also a monotonous match-the-color game.

We will be baking down the materials prior to export. That way, our Unreal artists will only need to import a singular texture map
per channel and it will be 100% faithful to what the Blender artist intended. This will be non-destrcutive to the Blender artists,
in case they make an edit to their work after it has already been exported for Unreal. 

LIGHTS
The lighting workflow in Blender is very intuitive, but many parameters set don't transfer well to Unreal.
Some light settings in Blender have counterparts in Unreal, however they might not have the same attribute name.
We will attempt to close the gap between each program's light systems in order to transfer a near-complete match.
The result will never be 1:1, but it's closer than a full remake of the light setup in Unreal. 


GEOMETRY
This is literally just the mesh objects exported as FBX. 
The material data will connect to the baked texture maps.


EXAMPOLE BAKE CODE:import bpy
# i guess the object must be selected, add this to the dict?
# the IMG TEX node must also be selected
def bake_all_materials():
    # Set render engine to Cycles (required for baking)
    bpy.context.scene.render.engine = 'CYCLES'
    
    # Get the active object
    obj = bpy.context.active_object
    
    if obj is None or obj.type != 'MESH':
        print("Please select a mesh object")
        return
    
    # Create new image textures for each material ##### KEEP AN EYE ON THIS PART!!!!!!!!!! $$$$$$$$$
    for mat in obj.data.materials:
        if mat is None:
            continue
            
        # Create a new image for baking
        image_name = f"{mat.name}_baked"
        bake_image = bpy.data.images.new(
            name=image_name,
            width=1024,  # Adjust resolution as needed
            height=1024
        )
        
        # Create a new texture node and assign the image
        nodes = mat.node_tree.nodes
        texture_node = nodes.new('ShaderNodeTexImage')
        texture_node.image = bake_image
        
        # Select the nodes for baking
        for node in nodes:
            node.select = False
        texture_node.select = True
        nodes.active = texture_node
        
        # Bake the material
        bpy.ops.object.bake(
            type='DIFFUSE',  # Change type based on what you want to bake
            pass_filter={'COLOR'},
            use_selected_to_active=False,
            margin=16
        )
        
        # Save the baked image
        bake_image.filepath_raw = f"//{image_name}.png"  # Adjust path as needed
        bake_image.file_format = 'PNG'
        bake_image.save()

# Run the function
bake_all_materials()


# keeping for reference
# https://docs.blender.org/api/current/bpy.ops.object.html#bpy.ops.object.bake
# https://docs.blender.org/api/current/bpy.types.BakeSettings.html
# bpy.context.scene.render.bake.use_selected_to_active = True
    bpy.context.scene.render.bake.margin = 16