scripts/modules/bpy_hydra.py

@@ -38,7 +38,6 @@ __all__ = (
 
 import os
 import platform
-import traceback
 from pathlib import Path
 
 import bpy
@@ -107,21 +106,14 @@ def export_mtlx(material):
     """ Exports material to .mtlx file. It is called from Blender source code. """
     try:
         import materialx.utils as mx_utils
-
-        doc = mx_utils.export(material, None)
-        if not doc:
-            return ""
-
-        mtlx_file = mx_utils.get_temp_file(".mtlx", f"mat_{material.as_pointer():016x}")
-        mx_utils.export_to_file(doc, mtlx_file, export_deps=True, copy_deps=False)
-        return str(mtlx_file)
-
     except ImportError:
         print("ERROR: no MaterialX addon available")
+        return ""
 
-    except:
-        # This is a placeholder, this code will be moved to C part later
-        # This code shouldn't raise any exception due to breaking refcounts on RenderEngine
-        traceback.print_exc()
+    doc = mx_utils.export(material, None)
+    if not doc:
+        return ""
 
-    return ""
+    mtlx_file = mx_utils.get_temp_file(".mtlx", f"mat_{material.as_pointer():016x}")
+    mx_utils.export_to_file(doc, mtlx_file, export_deps=True, copy_deps=False)
+    return str(mtlx_file)

source/blender/render/hydra/scene_delegate/material.cc

@@ -68,8 +68,28 @@ void MaterialData::init()
     Py_DECREF(result);
   }
   else {
-    CLOG_ERROR(LOG_RENDER_HYDRA_SCENE, "Export error for %s", id->name);
-    PyErr_Print();
+    /* Clearing and logging exception data */
+    PyObject *type, *value, *traceback;
+    PyErr_Fetch(&type, &value, &traceback);
+    PyErr_NormalizeException(&type, &value, &traceback);
+    std::string err_str = ((PyTypeObject *)type)->tp_name;
+    if (value) {
+      PyObject *pstr = PyObject_Str(value);
+      err_str += ": ";
+      err_str += PyUnicode_AsUTF8(pstr);
+      Py_DECREF(pstr);
+    }
+    CLOG_ERROR(LOG_RENDER_HYDRA_SCENE,
+               "Export error for %s (%s): %s",
+               prim_id.GetText(),
+               id->name,
+               err_str.c_str());
+    if (traceback) {
+      PyTraceBack_Print(traceback, PySys_GetObject("stderr"));
+    }
+    Py_XDECREF(traceback);
+    Py_XDECREF(value);
+    Py_DECREF(type);
   }
   Py_DECREF(module);
 

source/blender/render/hydra/scene_delegate/mesh.cc

@@ -17,7 +17,7 @@ namespace blender::render::hydra {
 MeshData::MeshData(BlenderSceneDelegate *scene_delegate,
                    Object *object,
                    pxr::SdfPath const &prim_id)
-    : ObjectData(scene_delegate, object, prim_id)
+    : ObjectData(scene_delegate, object, prim_id), parent_(object->parent)
 {
 }
 

source/blender/render/hydra/scene_delegate/mesh.h

@@ -42,6 +42,7 @@ class MeshData : public ObjectData {
   pxr::VtVec3fArray normals_;
 
   MaterialData *mat_data_ = nullptr;
+  Object *parent_;
 };
 
 }  // namespace blender::render::hydra