[Bf-extensions-cvs] [0f84063c] blender2.8: OBJ IO: Change specular IO conversion.
Bastien Montagne
noreply at git.blender.org
Tue Oct 16 20:01:18 CEST 2018
Commit: 0f84063c580811e14241bda234508a2622f0fcae
Author: Bastien Montagne
Date: Tue Oct 16 16:34:37 2018 +0200
Branches: blender2.8
https://developer.blender.org/rBA0f84063c580811e14241bda234508a2622f0fcae
OBJ IO: Change specular IO conversion.
Conversion from phong exponent to Principled BSDF is expected to be
quadratic afaik, not linear.
===================================================================
M io_scene_obj/__init__.py
M io_scene_obj/export_obj.py
M io_scene_obj/import_obj.py
===================================================================
diff --git a/io_scene_obj/__init__.py b/io_scene_obj/__init__.py
index ac396b7e..ab977ca9 100644
--- a/io_scene_obj/__init__.py
+++ b/io_scene_obj/__init__.py
@@ -21,7 +21,7 @@
bl_info = {
"name": "Wavefront OBJ format",
"author": "Campbell Barton, Bastien Montagne",
- "version": (3, 4, 1),
+ "version": (3, 4, 2),
"blender": (2, 80, 0),
"location": "File > Import-Export",
"description": "Import-Export OBJ, Import OBJ mesh, UV's, materials and textures",
diff --git a/io_scene_obj/export_obj.py b/io_scene_obj/export_obj.py
index f3b92afd..a147a493 100644
--- a/io_scene_obj/export_obj.py
+++ b/io_scene_obj/export_obj.py
@@ -73,9 +73,11 @@ def write_mtl(scene, filepath, path_mode, copy_set, mtl_dict):
use_mirror = mat_wrap.metallic != 0.0
use_transparency = mat_wrap.transmission != 0.0
- # Convert from principled roughness to 0 - 1000 specular range.
- # XXX Basic linear conversion, what would be best-matching formula here?
- fw('Ns %.6f\n' % ((1.0 - mat_wrap.roughness) * 1000))
+ # XXX Totally empirical conversion, trying to adapt it
+ # (from 1.0 - 0.0 Principled BSDF range to 0.0 - 900.0 OBJ specular exponent range)...
+ spec = (1.0 - mat_wrap.roughness) * 30
+ spec *= spec
+ fw('Ns %.6f\n' % spec)
# Ambient
if use_mirror:
diff --git a/io_scene_obj/import_obj.py b/io_scene_obj/import_obj.py
index 916ff313..cb18f911 100644
--- a/io_scene_obj/import_obj.py
+++ b/io_scene_obj/import_obj.py
@@ -93,6 +93,8 @@ def create_materials(filepath, relpath,
Create all the used materials in this obj,
assign colors and images to the materials from all referenced material libs
"""
+ from math import sqrt
+
DIR = os.path.dirname(filepath)
context_material_vars = set()
@@ -303,8 +305,9 @@ def create_materials(filepath, relpath,
emit_colors[:] = [
float_func(line_split[1]), float_func(line_split[2]), float_func(line_split[3])]
elif line_id == b'ns':
- # XXX Basic linear conversion, what would be best-matching formula here?
- context_mat_wrap.roughness = 1.0 - (float_func(line_split[1]) / 1000)
+ # XXX Totally empirical conversion, trying to adapt it
+ # (from 0.0 - 900.0 OBJ specular exponent range to 1.0 - 0.0 Principled BSDF range)...
+ context_mat_wrap.roughness = 1.0 - (sqrt(float_func(line_split[1])) / 30)
context_material_vars.add("roughness")
elif line_id == b'ni': # Refraction index (between 0.001 and 10).
context_mat_wrap.ior = float_func(line_split[1])
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