1. Add a mirror function into CQ class(wrap) and Shape class(implement); 2. To get precise BoundBox, add tessellate(0.000001) in the BoundBox function implement......

cadquery/cq.py

@@ -742,6 +742,19 @@ class CQ(object):
         return self.newObject([o.rotate(axisStartPoint, axisEndPoint, angleDegrees)
                                for o in self.objects])
 
+    def mirror(self, mirrorPlane="XY", basePointVector=(0, 0, 0)):
+	"""
+	Mirror a single CQ object. This operation is the same as in the FreeCAD PartWB's mirroring
+
+	:param mirrorPlane: the plane to mirror about
+	:type mirrorPlane: string, one of "XY", "YX", "XZ", "ZX", "YZ", "ZY" the planes
+	:param basePointVector: the base point to mirror about
+	:type basePointVector: tuple
+	"""
+	newS = self.newObject([self.objects[0].mirror(mirrorPlane, basePointVector)])
+	return newS.first()
+
+
     def translate(self, vec):
         """
         Returns a copy of all of the items on the stack moved by the specified translation vector.

cadquery/freecad_impl/shapes.py

@@ -185,8 +185,22 @@ class Shape(object):
         return self.wrapped.isValid()
 
     def BoundingBox(self):
+	self.wrapped.tessellate(0.000001)
         return BoundBox(self.wrapped.BoundBox)
 
+    def mirror(self, mirrorPlane="XY", basePointVector=(0, 0, 0)):
+	if mirrorPlane == "XY" or mirrorPlane== "YX":
+	    mirrorPlaneNormalVector = FreeCAD.Base.Vector(0, 0, 1)
+	elif mirrorPlane == "XZ" or mirrorPlane == "ZX":
+	    mirrorPlaneNormalVector = FreeCAD.Base.Vector(0, 1, 0)
+	elif mirrorPlane == "YZ" or mirrorPlane == "ZY":
+	    mirrorPlaneNormalVector = FreeCAD.Base.Vector(1, 0, 0)
+
+        if type(basePointVector) == tuple:
+            basePointVector = Vector(basePointVector)
+
+	return Shape.cast(self.wrapped.mirror(basePointVector.wrapped, mirrorPlaneNormalVector))
+
     def Center(self):
         # A Part.Shape object doesn't have the CenterOfMass function, but it's wrapped Solid(s) does
         if isinstance(self.wrapped, FreeCADPart.Shape):