materialx/material/properties.py

@@ -84,7 +84,6 @@ class MaterialProperties(MaterialXProperties):
 
         return mtlx_file, doc
 
-
     def convert_to_materialx(self, obj: bpy.types.Object = None):
         mat = self.id_data
         output_node = self.output_node
@@ -109,6 +108,7 @@ class MaterialProperties(MaterialXProperties):
 
         mtlx_file = get_temp_file(".mtlx",
                                   f'{mat.name}_{self.mx_node_tree.name if self.mx_node_tree else ""}')
+
         mx.writeToXmlFile(doc, str(mtlx_file))
         search_path = mx.FileSearchPath(str(mtlx_file.parent))
         search_path.append(str(MX_LIBS_DIR))

materialx/utils.py

@@ -14,7 +14,6 @@ from . import ADDON_ALIAS
 from . import logging
 log = logging.Log('utils')
 
-
 ADDON_ROOT_DIR = Path(__file__).parent
 ADDON_DATA_DIR = Path(bpy.utils.user_resource('SCRIPTS', path=f"addons/{ADDON_ALIAS}_data", create=True))
 BL_DATA_DIR = Path(bpy.utils.resource_path('LOCAL')) / "datafiles/materialx"
@@ -444,3 +443,32 @@ def update_ui(area_type='PROPERTIES', region_type='WINDOW'):
                 for region in area.regions:
                     if region.type == region_type:
                         region.tag_redraw()
+
+
+def update_materialx_data(depsgraph, materialx_data):
+    from .node_tree import MxNodeTree
+
+    if not depsgraph.updates:
+        return
+
+    for mx_node_tree in (upd.id for upd in depsgraph.updates if isinstance(upd.id, MxNodeTree)):
+        for material in bpy.data.materials:
+            if material.materialx.mx_node_tree and material.materialx.mx_node_tree.name == mx_node_tree.name:
+                doc = material.materialx.export(None)
+                if not doc:
+                    # log.warn("MX export failed", mat)
+                    continue
+
+                matx_data = next((mat for mat in materialx_data if mat[0] == material.name), None)
+
+                if not matx_data:
+                    mx_file = get_temp_file(".mtlx",
+                                            f'{material.name}{material.materialx.mx_node_tree.name if material.materialx.mx_node_tree else ""}',
+                                            False)
+
+                    mx.writeToXmlFile(doc, str(mx_file))
+                    surfacematerial = next((node for node in doc.getNodes()
+                                            if node.getCategory() == 'surfacematerial'))
+                    materialx_data.append((material.name, str(mx_file), surfacematerial.getName()))
+                else:
+                    mx.writeToXmlFile(doc, str(matx_data[1]))