Add enlarge method to BoundBox

cadquery/occ_impl/geom.py

@@ -846,6 +846,22 @@ def add(
 
         return BoundBox(tmp)
 
+    def enlarge(self, tol: float) -> "BoundBox":
+        """Returns a modified (expanded) bounding box, expanded in all
+        directions by the tolerance value. 
+
+        This means that the minimum values of its X, Y and Z intervals
+        of the bounding box are reduced by the absolute value of tol, while 
+        the maximum values are increased by the same amount. 
+        """
+        tmp = Bnd_Box()
+        tmp.Add(self.wrapped)
+        tmp.SetGap(self.wrapped.GetGap())
+
+        tmp.Enlarge(tol)
+
+        return BoundBox(tmp)
+
     @staticmethod
     def findOutsideBox2D(bb1: "BoundBox", bb2: "BoundBox") -> Optional["BoundBox"]:
         """Compares bounding boxes

tests/test_cadquery.py

@@ -1778,6 +1778,25 @@ def testBoundingBox(self):
         self.assertAlmostEqual(0.0, bb.zmin, 2)
         self.assertAlmostEqual(100.0, bb.zmax, 2)
 
+    def testBoundBoxEnlarge(self):
+        """
+        Tests BoundBox.enlarge(). Confirms that the 
+        bounding box lengths are all enlarged by the
+        correct amount.
+        """
+
+        enlarge_tol = 2.0
+        bb = Workplane("XY").rect(10, 10).extrude(10).val().BoundingBox()
+        bb_enlarged = bb.enlarge(enlarge_tol)
+
+        self.assertTrue(bb_enlarged.isInside(bb))
+        self.assertAlmostEqual(bb_enlarged.xmin, bb.xmin - enlarge_tol, 2)
+        self.assertAlmostEqual(bb_enlarged.xmax, bb.xmax + enlarge_tol, 2)
+        self.assertAlmostEqual(bb_enlarged.ymin, bb.ymin - enlarge_tol, 2)
+        self.assertAlmostEqual(bb_enlarged.ymax, bb.ymax + enlarge_tol, 2)
+        self.assertAlmostEqual(bb_enlarged.zmin, bb.zmin - enlarge_tol, 2)
+        self.assertAlmostEqual(bb_enlarged.zmax, bb.zmax + enlarge_tol, 2)
+
     def testCutThroughAll(self):
         """
         Tests a model that uses more than one workplane