Misc algebra related fixes

src/build123d/build_common.py

@@ -366,9 +366,11 @@ class LocationList:
     @property
     def locations(self) -> list[Location]:
         """Current local locations globalized with current workplanes"""
+        context = WorkplaneList._get_context()
+        workplanes = context.workplanes if context else [Plane.XY]
         global_locations = [
             plane.to_location() * local_location
-            for plane in WorkplaneList._get_context().workplanes
+            for plane in workplanes
             for local_location in self.local_locations
         ]
         return global_locations

src/build123d/geometry.py

@@ -1217,20 +1217,29 @@ class Pos(Location):
         """Position by Vertex"""
 
     @overload
-    def __init__(self, x: float = 0, y: float = 0, z: float = 0):
+    def __init__(self, X: float = 0, Y: float = 0, Z: float = 0):
         """Position by X, Y, Z"""
 
-    def __init__(self, *args):
+    def __init__(self, *args, **kwargs):
+        position = [0,0,0]
         # VectorLike
         if len(args) == 1 and isinstance(args[0], (tuple, Vector)):
-            super().__init__(args[0])
+            position = list(args[0])
         # Vertex
         elif len(args) == 1 and isinstance(args[0], Iterable):
-            super().__init__(*list(args[0]))
+            position = list(args[0])
         # Values
         elif 1 <= len(args) <= 3 and all([isinstance(v, (float, int)) for v in args]):
             position = list(args) + [0] * (3 - len(args))
-            super().__init__(tuple(position))
+
+        if "X" in kwargs:
+            position[0] = kwargs["X"]
+        if "Y" in kwargs:
+            position[1] = kwargs["Y"]
+        if "Z" in kwargs:
+            position[2] = kwargs["Z"]
+
+        super().__init__(tuple(position))
 
 
 class Rot(Location):

src/build123d/topology.py

@@ -1097,7 +1097,7 @@ class Shape(NodeMixin):
         joints: dict[str, Joint] = None,
         parent: Compound = None,
         children: list[Shape] = None,
-        is_alg: bool = False,
+        is_alg: bool = True,
     ):
         self.wrapped = downcast(obj) if obj else None
         self.for_construction = False
@@ -3263,7 +3263,7 @@ class AlgebraMixin:
                 f"Cannot combine objects of different dimensionality: {self._dim} and {objs[0]._dim}"
             )
 
-        if self._dim == 0:  # Cover addition of empty BuildPart with another object
+        if not self.wrapped:  # Cover addition of empty BuildPart with another object
             if mode == Mode.ADD:
                 if len(objs) == 1:
                     compound = copy.deepcopy(objs[0])