Fix #102594: USD Import: mask multiple prim paths.

These changes enhance the prim_path_mask USD import option to allow masking on multiple paths.

Changed the prim_path_mask import property to a string of arbitrary size.

Multiple paths may be specified in a list delimited by commas or semicolons.

Reviewed by Bastien and Matt McLin.

Pull Request: https://projects.blender.org/blender/blender/pulls/106974

source/blender/editors/io/io_usd.c

@@ -395,8 +395,7 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
 
   const bool create_collection = RNA_boolean_get(op->ptr, "create_collection");
 
-  char prim_path_mask[1024];
-  RNA_string_get(op->ptr, "prim_path_mask", prim_path_mask);
+  char *prim_path_mask = RNA_string_get_alloc(op->ptr, "prim_path_mask", NULL, 0, NULL);
 
   const bool import_guide = RNA_boolean_get(op->ptr, "import_guide");
   const bool import_proxy = RNA_boolean_get(op->ptr, "import_proxy");
@@ -448,6 +447,7 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
                                    .import_meshes = import_meshes,
                                    .import_volumes = import_volumes,
                                    .import_shapes = import_shapes,
+                                   .prim_path_mask = prim_path_mask,
                                    .import_subdiv = import_subdiv,
                                    .import_instance_proxies = import_instance_proxies,
                                    .create_collection = create_collection,
@@ -464,7 +464,6 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
                                    .tex_name_collision_mode = tex_name_collision_mode,
                                    .import_all_materials = import_all_materials};
 
-  STRNCPY(params.prim_path_mask, prim_path_mask);
   STRNCPY(params.import_textures_dir, import_textures_dir);
 
   const bool ok = USD_import(C, filename, &params, as_background_job);
@@ -620,12 +619,14 @@ void WM_OT_usd_import(struct wmOperatorType *ot)
   RNA_def_boolean(
       ot->srna, "read_mesh_colors", true, "Color Attributes", "Read mesh color attributes");
 
-  RNA_def_string(ot->srna,
-                 "prim_path_mask",
-                 NULL,
-                 1024,
-                 "Path Mask",
-                 "Import only the subset of the USD scene rooted at the given primitive");
+  RNA_def_string(
+      ot->srna,
+      "prim_path_mask",
+      NULL,
+      0,
+      "Path Mask",
+      "Import only the primitive at the given path and its descendents.  "
+      "Multiple paths may be specified in a list delimited by commas or semicolons");
 
   RNA_def_boolean(ot->srna, "import_guide", false, "Guide", "Import guide geometry");
 

source/blender/io/usd/intern/usd_capi_import.cc

@@ -202,7 +202,21 @@ static void import_startjob(void *customdata, bool *stop, bool *do_update, float
   *data->do_update = true;
   *data->progress = 0.1f;
 
-  pxr::UsdStageRefPtr stage = pxr::UsdStage::Open(data->filepath);
+  std::string prim_path_mask(data->params.prim_path_mask);
+  pxr::UsdStagePopulationMask pop_mask;
+  if (!prim_path_mask.empty()) {
+    const std::vector<std::string> mask_tokens = pxr::TfStringTokenize(prim_path_mask, ",;");
+    for (const std::string &tok : mask_tokens) {
+      pxr::SdfPath prim_path(tok);
+      if (!prim_path.IsEmpty()) {
+        pop_mask.Add(prim_path);
+      }
+    }
+  }
+
+  pxr::UsdStageRefPtr stage = pop_mask.IsEmpty() ?
+                                  pxr::UsdStage::Open(data->filepath) :
+                                  pxr::UsdStage::OpenMasked(data->filepath, pop_mask);
 
   if (!stage) {
     WM_reportf(RPT_ERROR, "USD Import: unable to open stage to read %s", data->filepath);
@@ -376,6 +390,8 @@ static void import_endjob(void *customdata)
       break;
   }
 
+  MEM_SAFE_FREE(data->params.prim_path_mask);
+
   WM_main_add_notifier(NC_SCENE | ND_FRAME, data->scene);
   report_job_duration(data);
 }

source/blender/io/usd/intern/usd_reader_stage.cc

@@ -312,19 +312,6 @@ void USDStageReader::collect_readers(Main *bmain)
   /* Iterate through the stage. */
   pxr::UsdPrim root = stage_->GetPseudoRoot();
 
-  std::string prim_path_mask(params_.prim_path_mask);
-
-  if (!prim_path_mask.empty()) {
-    pxr::UsdPrim prim = stage_->GetPrimAtPath(pxr::SdfPath(prim_path_mask));
-    if (prim.IsValid()) {
-      root = prim;
-    }
-    else {
-      std::cerr << "WARNING: Prim Path Mask " << prim_path_mask
-                << " does not specify a valid prim.\n";
-    }
-  }
-
   stage_->SetInterpolationType(pxr::UsdInterpolationType::UsdInterpolationTypeHeld);
   collect_readers(bmain, root);
 }

source/blender/io/usd/usd.h

@@ -67,7 +67,7 @@ struct USDImportParams {
   bool import_meshes;
   bool import_volumes;
   bool import_shapes;
-  char prim_path_mask[1024];
+  char *prim_path_mask;
   bool import_subdiv;
   bool import_instance_proxies;
   bool create_collection;