Fix orientation inconsistenceis.

src/scenic/core/regions.py

@@ -886,7 +886,9 @@ def sampleGiven(self, value):
             dimensions=value[self.dimensions],
             position=value[self.position],
             rotation=value[self.rotation],
-            orientation=value[self.orientation],
+            orientation=True
+            if self.__dict__.get("_usingDefaultOrientation", False)
+            else value[self.orientation],
             tolerance=self.tolerance,
             centerMesh=self.centerMesh,
             onDirection=self.onDirection,
@@ -905,7 +907,11 @@ def evaluateInner(self, context):
         dimensions = valueInContext(self.dimensions, context)
         position = valueInContext(self.position, context)
         rotation = valueInContext(self.rotation, context)
-        orientation = valueInContext(self.orientation, context)
+        orientation = (
+            True
+            if self.__dict__.get("_usingDefaultOrientation", False)
+            else valueInContext(self.orientation, context)
+        )
 
         return cls(
             mesh,
@@ -1740,7 +1746,6 @@ def getSurfaceRegion(self):
         return MeshSurfaceRegion(
             self.mesh,
             self.name,
-            orientation=self.orientation,
             tolerance=self.tolerance,
             centerMesh=False,
             onDirection=self.onDirection,
@@ -1779,21 +1784,23 @@ class MeshSurfaceRegion(MeshRegion):
         onDirection: The direction to use if an object being placed on this region doesn't specify one.
     """
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+    def __init__(self, *args, orientation=True, **kwargs):
+        if orientation is True:
+            orientation = VectorField(
+                "DefaultSurfaceVectorField", lambda pos: self.getFlatOrientation(pos)
+            )
+            self._usingDefaultOrientation = True
+        else:
+            self._usingDefaultOrientation = False
+
+        super().__init__(*args, orientation=orientation, **kwargs)
 
         # Validate dimensions
         if self.dimensions is not None:
             for dim, name in zip(self.dimensions, ("width", "length", "height")):
                 if dim < 0:
                     raise ValueError(f"{name} of MeshSurfaceRegion must be nonnegative")
 
-        # Set default orientation to one inferred from face norms if none is provided.
-        if self.orientation is None:
-            self.orientation = VectorField(
-                "DefaultSurfaceVectorField", lambda pos: self.getFlatOrientation(pos)
-            )
-
     # Property testing methods #
     @distributionFunction
     def intersects(self, other, triedReversed=False):
@@ -1931,7 +1938,6 @@ def getVolumeRegion(self):
         return MeshVolumeRegion(
             self.mesh,
             self.name,
-            orientation=self.orientation,
             tolerance=self.tolerance,
             centerMesh=False,
             onDirection=self.onDirection,
@@ -3746,8 +3752,6 @@ class ViewRegion(MeshVolumeRegion):
         name: An optional name to help with debugging.
         position: An optional position, which determines where the center of the region will be.
         rotation: An optional Orientation object which determines the rotation of the object in space.
-        orientation: An optional vector field describing the preferred orientation at every point in
-          the region.
         angleCutoff: How close to 180/360 degrees an angle has to be to be mapped to that value.
         tolerance: Tolerance for collision computations.
     """
@@ -3759,7 +3763,6 @@ def __init__(
         name=None,
         position=Vector(0, 0, 0),
         rotation=None,
-        orientation=None,
         angleCutoff=0.017,
         tolerance=1e-8,
     ):
@@ -3806,7 +3809,6 @@ def __init__(
             name=name,
             position=position,
             rotation=rotation,
-            orientation=orientation,
             tolerance=tolerance,
             centerMesh=False,
         )