fix(sim): Fix .obj mesh compose issue. (#46)

Author: HochCC

embodied_gen/data/convex_decomposer.py

@@ -45,16 +45,23 @@ def decompose_convex_coacd(
     mesh = coacd.Mesh(mesh.vertices, mesh.faces)
 
     result = coacd.run_coacd(mesh, **params)
-    combined = sum([trimesh.Trimesh(*m) for m in result])
+
+    meshes = []
+    for v, f in result:
+        meshes.append(trimesh.Trimesh(v, f))
 
     # Compute collision_scale because convex decomposition usually makes the mesh larger.
     if auto_scale:
-        convex_mesh_shape = np.ptp(combined.vertices, axis=0)
+        all_mesh = sum([trimesh.Trimesh(*m) for m in result])
+        convex_mesh_shape = np.ptp(all_mesh.vertices, axis=0)
         visual_mesh_shape = np.ptp(mesh.vertices, axis=0)
-        rescale = visual_mesh_shape / convex_mesh_shape
-        combined.vertices *= rescale
+        scale_factor *= visual_mesh_shape / convex_mesh_shape
+
+    combined = trimesh.Scene()
+    for mesh_part in meshes:
+        mesh_part.vertices *= scale_factor
+        combined.add_geometry(mesh_part)
 
-    combined.vertices *= scale_factor
     combined.export(outfile)
 
 

embodied_gen/validators/urdf_convertor.py

@@ -282,16 +282,12 @@ def generate_urdf(
                     d_params = dict(
                         threshold=0.05, max_convex_hull=100, verbose=False
                     )
-                    filename = f"{os.path.splitext(obj_name)[0]}_collision.ply"
+                    filename = f"{os.path.splitext(obj_name)[0]}_collision.obj"
                     output_path = os.path.join(mesh_folder, filename)
                     decompose_convex_mesh(
                         mesh_output_path, output_path, **d_params
                     )
-                    obj_filename = filename.replace(".ply", ".obj")
-                    trimesh.load(output_path).export(
-                        f"{mesh_folder}/{obj_filename}"
-                    )
-                    collision_mesh = f"{self.output_mesh_dir}/{obj_filename}"
+                    collision_mesh = f"{self.output_mesh_dir}/{filename}"
                 except Exception as e:
                     logger.warning(
                         f"Convex decomposition failed for {output_path}, {e}."