Fix robot model artist for Blender

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 * Changed new artist registration to check if subclass.
+* Fixed `RobotModelArtist` for blender: missing abstract method impl and handle init order.
 
 ### Removed
 

src/compas_blender/artists/artist.py

@@ -21,11 +21,10 @@ class BlenderArtist(Artist):
     def __init__(self,
                  collection: Optional[Union[str, bpy.types.Collection]] = None,
                  **kwargs: Any):
-
-        super().__init__(**kwargs)
-
+        # Initialize collection before even calling super because other classes depend on that
         self._collection = None
         self.collection = collection
+        super().__init__(**kwargs)
 
     @property
     def collection(self) -> bpy.types.Collection:

src/compas_blender/artists/robotmodelartist.py

@@ -60,20 +60,28 @@ def create_geometry(self,
     def redraw(self, timeout: float = 0.0) -> None:
         bpy.ops.wm.redraw_timer(type='DRAW_WIN_SWAP', iterations=1, time_limit=timeout)
 
-    def clear(self) -> None:
-        compas_blender.delete_objects(self.collection.objects)
+    def _ensure_geometry(self):
+        if len(self.collection.objects) == 0:
+            self.create()
+
+    def draw(self) -> None:
+        self._ensure_geometry()
+        self.draw_visual()
 
     def draw_visual(self) -> None:
+        self._ensure_geometry()
         visuals = super(RobotModelArtist, self).draw_visual()
         for visual in visuals:
             visual.hide_set(False)
 
     def draw_collision(self) -> None:
+        self._ensure_geometry()
         collisions = super(RobotModelArtist, self).draw_collision()
         for collision in collisions:
             collision.hide_set(False)
 
     def draw_attached_meshes(self) -> None:
+        self._ensure_geometry()
         meshes = super(RobotModelArtist, self).draw_attached_meshes()
         for mesh in meshes:
             mesh.hide_set(False)