Update relation between frame and transformation

Author: Licini

CHANGELOG.md

@@ -11,6 +11,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* Changed `SceneObject.worldtransformation` to the multiplication of all transformations from the scene object to the root of the scene tree.
+* Changed `SceneObject.frame` to read-only result of `Frame.from_transformation(SceneObject.worldtransformation)`, representing the local coordinate system of the scene object in world coordinates.
+
 ### Removed
 
 

src/compas/scene/sceneobject.py

@@ -13,6 +13,7 @@
 from compas.colors import Color
 from compas.data import Data
 from compas.datastructures import TreeNode
+from compas.geometry import Frame
 from compas.geometry import Transformation
 
 from .context import clear
@@ -36,10 +37,8 @@ class SceneObject(TreeNode):
         The opacity of the object.
     show : bool, optional
         Flag for showing or hiding the object. Default is ``True``.
-    frame : :class:`compas.geometry.Frame`, optional
-        The local frame of the scene object, in relation to its parent frame.
     transformation : :class:`compas.geometry.Transformation`, optional
-        The local transformation of the scene object in relation to its frame.
+        The local transformation of the scene object in relation to its parent object.
     context : str, optional
         The context in which the scene object is created.
     **kwargs : dict
@@ -56,9 +55,9 @@ class SceneObject(TreeNode):
     guids : list[object]
         The GUIDs of the items drawn in the visualization context.
     frame : :class:`compas.geometry.Frame`
-        The local frame of the scene object, in relation to its parent frame.
+        The frame of the local coordinate system of the scene object.
     transformation : :class:`compas.geometry.Transformation`
-        The local transformation of the scene object in relation to its frame.
+        The local transformation of the scene object in relation to its parent object.
     worldtransformation : :class:`compas.geometry.Transformation`
         The transformation of the scene object in world coordinates.
     color : :class:`compas.colors.Color`
@@ -113,7 +112,6 @@ def __init__(
         self._item = item
         self._guids = []
         self._node = None
-        self._frame = frame
         self._transformation = transformation
         self._contrastcolor = None
         self.color = color or self.color
@@ -156,12 +154,7 @@ def guids(self):
     @property
     def frame(self):
         # type: () -> compas.geometry.Frame | None
-        return self._frame
-
-    @frame.setter
-    def frame(self, frame):
-        # type: (compas.geometry.Frame) -> None
-        self._frame = frame
+        return Frame.from_transformation(self.worldtransformation)
 
     @property
     def transformation(self):
@@ -176,21 +169,17 @@ def transformation(self, transformation):
     @property
     def worldtransformation(self):
         # type: () -> compas.geometry.Transformation
-        frame_stack = [self.frame] if self.frame else []
-        parent = self.parent
+        transformations = [self.transformation] if self.transformation else []
+        parent: SceneObject = self.parent
         while parent and not parent.is_root:
-            if parent.frame:
-                frame_stack.append(parent.frame)
+            if parent.transformation:
+                transformations.append(parent.transformation)
             parent = parent.parent
-        matrices = [Transformation.from_frame(f) for f in frame_stack]
-        if matrices:
-            worldtransformation = reduce(mul, matrices[::-1])
+        if transformations:
+            worldtransformation = reduce(mul, transformations[::-1])
         else:
             worldtransformation = Transformation()
 
-        if self.transformation:
-            worldtransformation *= self.transformation
-
         return worldtransformation
 
     @property

tests/compas/scene/test_scene.py

@@ -83,22 +83,19 @@ def test_sceneobject_auto_context_discovery_no_context(mocker):
     def test_sceneobject_transform():
         scene = Scene()
         sceneobj1 = scene.add(Box())
-        sceneobj1.frame = Frame([1.0, 0.0, 0.0], xaxis=[1.0, 0.0, 0.0], yaxis=[0.0, 1.0, 0.0])
         sceneobj1.transformation = Translation.from_vector([10.0, 0.0, 0.0])
-        assert sceneobj1.worldtransformation == sceneobj1.frame.to_transformation() * sceneobj1.transformation
+        assert sceneobj1.worldtransformation == Translation.from_vector([10.0, 0.0, 0.0])
+        assert sceneobj1.frame == Frame([10.0, 0.0, 0.0], [1.0, 0.0, 0.0], [0.0, 1.0, 0.0])
 
         sceneobj2 = scene.add(Box(), parent=sceneobj1)
-        sceneobj2.frame = Frame([1.0, 1.0, 0.0], xaxis=[1.0, 0.0, 0.0], yaxis=[0.0, 1.0, 0.0])
         sceneobj2.transformation = Translation.from_vector([10.0, 10.0, 0.0])
-        assert sceneobj2.worldtransformation == sceneobj1.frame.to_transformation() * sceneobj2.frame.to_transformation() * sceneobj2.transformation
+        assert sceneobj2.worldtransformation == sceneobj1.transformation * sceneobj2.transformation
+        assert sceneobj2.frame == Frame([20.0, 10.0, 0.0], [1.0, 0.0, 0.0], [0.0, 1.0, 0.0])
 
         sceneobj3 = scene.add(Box(), parent=sceneobj2)
-        sceneobj3.frame = Frame([1.0, 1.0, 1.0], xaxis=[0.0, 1.0, 0.0], yaxis=[1.0, 0.0, 0.0])
         sceneobj3.transformation = Translation.from_vector([10.0, 10.0, 10.0])
-        assert (
-            sceneobj3.worldtransformation
-            == sceneobj1.frame.to_transformation() * sceneobj2.frame.to_transformation() * sceneobj3.frame.to_transformation() * sceneobj3.transformation
-        )
+        assert sceneobj3.worldtransformation == sceneobj1.transformation * sceneobj2.transformation * sceneobj3.transformation
+        assert sceneobj3.frame == Frame([30.0, 20.0, 10.0], [1.0, 0.0, 0.0], [0.0, 1.0, 0.0])
 
     def test_scene_clear():
         scene = Scene()