[Bf-extensions-cvs] [eca1bdeb] blender-v3.3-release: glTF exporter: KHR_material_volume: thickness is now default to 0.0 (as in specification)

[Julien Duroure]

Commit: eca1bdeb88a35deeaec8f2969953dd6d503315a3
Author: Julien Duroure
Date:   Sat Aug 6 12:15:54 2022 +0200
Branches: blender-v3.3-release
https://developer.blender.org/rBAeca1bdeb88a35deeaec8f2969953dd6d503315a3

glTF exporter: KHR_material_volume: thickness is now default to 0.0 (as in specification)

===================================================================

M	io_scene_gltf2/__init__.py
M	io_scene_gltf2/blender/com/gltf2_blender_material_helpers.py
M	io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_volume.py

===================================================================

diff --git a/io_scene_gltf2/__init__.py b/io_scene_gltf2/__init__.py
index 6146be8a..3fb5ad4d 100755
--- a/io_scene_gltf2/__init__.py
+++ b/io_scene_gltf2/__init__.py
@@ -4,7 +4,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Scurest, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (3, 3, 22),
+    "version": (3, 3, 23),
     'blender': (3, 3, 0),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',
diff --git a/io_scene_gltf2/blender/com/gltf2_blender_material_helpers.py b/io_scene_gltf2/blender/com/gltf2_blender_material_helpers.py
index 0bca9933..7dfef7dc 100755
--- a/io_scene_gltf2/blender/com/gltf2_blender_material_helpers.py
+++ b/io_scene_gltf2/blender/com/gltf2_blender_material_helpers.py
@@ -14,7 +14,7 @@ def create_settings_group(name):
     gltf_node_group = bpy.data.node_groups.new(name, 'ShaderNodeTree')
     gltf_node_group.inputs.new("NodeSocketFloat", "Occlusion")
     thicknessFactor  = gltf_node_group.inputs.new("NodeSocketFloat", "Thickness")
-    thicknessFactor.default_value = 1.0
+    thicknessFactor.default_value = 0.0
     gltf_node_group.nodes.new('NodeGroupOutput')
     gltf_node_group_input = gltf_node_group.nodes.new('NodeGroupInput')
     gltf_node_group_input.location = -200, 0
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_volume.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_volume.py
index 57b00700..8a69e3f6 100644
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_volume.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_materials_volume.py
@@ -27,12 +27,12 @@ def export_volume(blender_material, export_settings):
 
     thicknesss_socket = gltf2_blender_get.get_socket_old(blender_material, 'Thickness')
     if thicknesss_socket is None:
-        volume_extension['thicknessFactor'] = 1.0
+        # If no thickness (here because there is no glTF Material Output node), no volume extension export
+            return None, None
 
     density_socket = gltf2_blender_get.get_socket(blender_material, 'Density', volume=True)
     attenuation_color_socket = gltf2_blender_get.get_socket(blender_material, 'Color', volume=True)
-    if density_socket is None or attenuation_color_socket is None:
-        return None, None
+    # Even if density or attenuation are not set, we export volume extension
 
     if isinstance(attenuation_color_socket, bpy.types.NodeSocket):
         rgb = gltf2_blender_get.get_const_from_default_value_socket(attenuation_color_socket, kind='RGB')