blender: fancy wireframe rendering

docs/source/blender.md

@@ -15,11 +15,17 @@ python -m kiui.cli.blender_render --help
 
 # example
 python -m kiui.cli.blender_render --mesh chest.glb --gpu 0 --depth --normal --albedo --camera --blend
+
+# example with wireframe
+python -m kiui.cli.blender_render --mesh chest.glb --wireframe
 ```
 
+The code has many things hard-coded to avoid complex configs (e.g., camera position, wire frame color and width). Since there is no other dependency, you could copy and modify this single file to your own project.
+
 Features include:
 * Set which GPU to use with `--gpu 0` for `CYCLES` rendering engine.
 * Render with random built-in HDRI environment texture shading (check `assets/blender_lights`).
 * Empirical cleaning of the scene (remove the annoying plane under the object).
 * Optionally render depth (`exr`), normal.
-* Optionally render PBR (albedo, metallic, roughness).
+* Optionally render PBR (albedo, metallic, roughness).
+* Render wireframe.

kiui/cli/blender_render.py

@@ -291,10 +291,14 @@ def get_calibration_matrix_K_from_blender(camera):
 
 
 def load_object(mesh):
-    if mesh.endswith(".glb"):
+    if mesh.lower().endswith(".glb"):
         bpy.ops.import_scene.gltf(filepath=mesh, merge_vertices=True)
-    elif mesh.endswith(".fbx"):
+    elif mesh.lower().endswith(".fbx"):
         bpy.ops.import_scene.fbx(filepath=mesh)
+    elif mesh.lower().endswith(".obj"):
+        bpy.ops.wm.obj_import(filepath=mesh)
+    elif mesh.lower().endswith(".ply"):
+        bpy.ops.wm.ply_import(filepath=mesh)
     else:
         raise ValueError(f"Unsupported file type: {mesh}")
 
@@ -342,6 +346,57 @@ def normalize_scene(bound=0.9):
         obj.matrix_world.translation += offset
     bpy.ops.object.select_all(action="DESELECT")
 
+MAT_ID = 0
+
+def create_simple_material(color, mat_name=None):
+    global MAT_ID
+
+    if mat_name is None:
+        mat_name = f"assigned_mat_{MAT_ID:06d}"
+        MAT_ID += 1
+
+    mat = bpy.data.materials.new(mat_name)
+    mat.use_nodes = True
+    tree = mat.node_tree
+
+    # set principled BSDF
+    tree.nodes["Principled BSDF"].inputs['Base Color'].default_value = color
+    tree.nodes["Principled BSDF"].inputs['Roughness'].default_value = 0.3
+    tree.nodes["Principled BSDF"].inputs['Sheen Tint'].default_value = [0, 0, 0, 1]
+    tree.nodes["Principled BSDF"].inputs['Specular IOR Level'].default_value = 0.5
+    tree.nodes["Principled BSDF"].inputs['IOR'].default_value = 1.45
+    tree.nodes["Principled BSDF"].inputs['Transmission Weight'].default_value = 0
+    tree.nodes["Principled BSDF"].inputs['Coat Roughness'].default_value = 0
+
+    return mat
+
+# enable wireframe rendering
+# parameters are hard-coded for now
+def enable_wireframe():
+    for obj in bpy.data.objects:
+        if obj.type == 'MESH':
+            bpy.context.view_layer.objects.active = obj
+            bpy.ops.object.modifier_add(type='WIREFRAME')
+            bpy.context.object.modifiers["Wireframe"].use_replace = False # do not replace the original mesh
+            bpy.context.object.modifiers["Wireframe"].thickness = 0.01 # thickness of wireframe
+            bpy.context.object.modifiers["Wireframe"].use_even_offset = True # even thickness
+            # use a different color for surface and wireframe
+            surface_mat = create_simple_material((0.20, 0.50, 1, 1), mat_name="surface_mat") # blue surface, color is a tuple of 4 float (in [0, 1])
+            obj.data.materials.append(surface_mat) # 0, default material for surface
+            wireframe_mat = create_simple_material((1, 1, 1, 1), mat_name="wireframe_mat") # white wireframe
+            obj.data.materials.append(wireframe_mat) # 1
+            bpy.context.object.modifiers["Wireframe"].material_offset = 1
+
+
+def disable_wireframe():
+    for obj in bpy.data.objects:
+        if obj.type == 'MESH':
+            bpy.context.view_layer.objects.active = obj
+            try:
+                bpy.ops.object.modifier_remove(modifier="Wireframe")
+            except:
+                pass
+
 
 def main(args):
 
@@ -364,11 +419,17 @@ def main(args):
     clear_animation()
     normalize_scene(bound=args.bound)
 
-    # load random hdri
-    hdri_paths = glob.glob(os.path.join(os.path.dirname(os.path.abspath(__file__)), '../assets/blender_lights/*.exr'))
-    random_hdri_path = random.choice(hdri_paths)
-    print(f'[INFO] using hdri: {random_hdri_path}')
-    refs['node_hdri'].image = bpy.data.images.load(random_hdri_path)
+    # load random hdri if not specified
+    if args.hdri_path is None:
+        hdri_paths = glob.glob(os.path.join(os.path.dirname(os.path.abspath(__file__)), '../assets/blender_lights/*.exr'))
+        args.hdri_path = random.choice(hdri_paths)
+
+    print(f'[INFO] using hdri: {args.hdri_path}')
+    refs['node_hdri'].image = bpy.data.images.load(args.hdri_path)
+
+    # enable wireframe rendering
+    if args.wireframe:
+        enable_wireframe()
 
     # orbit camera
     cam.data.angle = np.deg2rad(args.fovy)
@@ -460,7 +521,9 @@ def main(args):
     parser.add_argument('--overwrite', action='store_true')
 
     # rendering parameters
-    parser.add_argument("--resolution", type=int, default=512)
+    parser.add_argument("--resolution", type=int, default=1024)
+    parser.add_argument("--hdri_path", type=str, default=None, help='path to hdri (exr), if not provided, random hdri will be used')
+    parser.add_argument("--wireframe", action='store_true', help='enable wireframe rendering')
     parser.add_argument("--bound", type=float, default=0.9)
     parser.add_argument("--radius", type=float, default=4.5)
     parser.add_argument("--fovy", type=float, default=30)