The motivation is to keep backward compatibility after deprecating
`material.use_nodes()` and `world.use_nodes`. For example the
following script would behave the same way in 4.5 and 5.0:
```python
mat = bpy.data.materials.new("My new mat")
mat.use_nodes = True
```
Pull Request: https://projects.blender.org/blender/blender/pulls/147052
"Use Nodes" was removed in the compositor to simplify the compositing
workflow. This introduced a slight inconsistency with the Shader Node
Editor.
This PR removes "Use Nodes" for object materials.
For Line Style, no changes are planned (not sure how to preserve
compatibility yet).
This simplifies the state of objects; either they have a material or
they don't.
Backward compatibility:
- If Use Nodes is turned Off, new nodes are added to the node tree to
simulate the same material:
- DNA: Only `use_nodes` is marked deprecated
- Python API:
- `material.use_nodes` is marked deprecated and will be removed in
6.0. Reading it always returns `True` and setting it has no effect.
- `material.diffuse_color`, `material.specular` etc.. Are not used by
EEVEE anymore but are kept because they are used by Workbench.
Forward compatibility:
Always enable 'Use Nodes' when writing blend files.
Known Issues:
Some UI tests are failing on macOS
Pull Request: https://projects.blender.org/blender/blender/pulls/141278
Part of https://projects.blender.org/blender/blender/pulls/141278
Blend files compatibility:
If a World exists and "Use Nodes" is disabled, we add new nodes to the
existing node tree (or create one if it doesn't) that emulates the
behavior of a world without a node tree. This ensures backward and
forward compatibility.
Python API compatibility:
- `world.use_nodes` was removed from Python API => **Breaking change**
- `world.color` is still being used by Workbench, so it stays there,
although it has no effect anymore when using Cycles or EEVEE.
Python API changes:
Creating a World using `bpy.data.worlds.new()` now creates a World with
an empty (embedded) node tree. This was necessary to enable Python
scripts to add nodes without having to create a node tree (which is
currently not possible, because World node trees are embedded).
Pull Request: https://projects.blender.org/blender/blender/pulls/142342
- Wrap the closing parenthesis onto it's own line
which makes assignments to the return value
read better.
- Reduce right-shift with multi-line function calls.
- Replace f-string with str.format
- Comment type annotations.
- Use double-quote for non-enum strings.
- Use single instead of double-underscores for private functions.
EEVEE-Next world volume are infinite like Cycles. EEVEE-Classic world volumes
end at the clip_end of the camera/viewport. This can lead to confusion as
it would render different then expected.
This PR adds an operator to convert a world volume into a mesh volume. The
operator can be found in the shader editor (world mode) and in the properties
panel/World/Volume.
**Why an operator?**
As this alters the content of the scene we want the artist to be in control of
the conversion. Doing it automatic lead to a lot of complexity and cases that
might not be expected by the user.
Pull Request: https://projects.blender.org/blender/blender/pulls/119734
