Added fix for tapered extrusions depending on version of CadQuery

CHANGELOG.md

@@ -7,3 +7,4 @@
 - v.0.5.1 - Update to fix setup.py issues
 - v.0.5.4 - Added new helper functions in cq_helpers. Added new object arrangers i cq_layout. New Makefile
 - v.0.5.6 - Added basic drafted solid builders (cq_basic.py). Solids can be hollow with different combinations of wall/floor/roof thicknesses. Added inverse_fillet and inverse_chamfer helpers
+- v.0.5.8 - Added automatic compensation for height of tapered extrusions depending on CadQuery version

README.md

@@ -578,7 +578,7 @@ r = r.inverse_fillet("<Z", 1.0)
 - v.0.5.3 - Updated with new helpers and updated setup.py
 - v.0.5.4 - Added new helper functions in cq_helpers. Added new object arrangers i cq_layout. New Makefile
 - v.0.5.6 - Added basic drafted solid builders (cq_basic.py). Solids can be hollow with different combinations of wall/floor/roof thicknesses. Added inverse_fillet and inverse_chamfer helpers
-
+- v.0.5.8 - Added automatic compensation for height of tapered extrusions depending on CadQuery version
 
 ## Authors
 

cqkit/__init__.py

@@ -4,7 +4,7 @@
 
 # fmt: off
 __project__ = 'cqkit'
-__version__ = '0.5.7'
+__version__ = '0.5.8'
 # fmt: on
 
 VERSION = __project__ + "-" + __version__

cqkit/cq_helpers.py

@@ -35,14 +35,24 @@
 
 from cqkit.cq_selectors import HasCoordinateSelector, SharedVerticesWithObjectSelector
 
+# Special test to see which version of CadQuery is installed and
+# therefore if any compensation is required for extruded zlen
+# CQ versions < 2.4.0 typically require zlen correction, i.e.
+# scaling the vertical extrusion extent by 1/cos(taper)
+ZLEN_OK = False
+_r = cq.Workplane("XY").rect(2, 2).extrude(1, taper=45)
+_bb = _r.vals()[0].BoundingBox()
+if abs(_bb.zlen - 1.0) < 1e-3:
+    ZLEN_OK = True
+
 
 def multi_extrude(obj, levels, face=">Z"):
     """Extrudes successive layers of a base solid from a reference face.
     Each extrusion layer is specified either as a fixed dimension offset or
     a tuple of offset and taper angle."""
     for level in levels:
         if isinstance(level, (tuple, list)):
-            cl = level[0] / cos(radians(level[1]))
+            cl = level[0] if ZLEN_OK else level[0] / cos(radians(level[1]))
             obj = obj.faces(face).wires().toPending().extrude(cl, taper=level[1])
         else:
             obj = obj.faces(face).wires().toPending().extrude(level)