involute gear: add parameter pitch

+ minimal fix for rack

freecad/gears/features.py

@@ -110,6 +110,8 @@ class InvoluteGear(object):
                         "gear", "gear_parameter", "test")
         obj.addProperty("App::PropertyLength", "dw",
                         "computed", "pitch diameter", 1)
+        obj.addProperty("App::PropertyLength", "transverse_pitch",
+                        "computed", "transverse_pitch", 1)
         obj.gear = self.involute_tooth
         obj.simple = False
         obj.undercut = False
@@ -170,7 +172,9 @@ class InvoluteGear(object):
             rw = fp.gear.dw / 2
             fp.Shape = Part.makeCylinder(rw, fp.height.Value)
 
+        # computed properties
         fp.dw = "{}mm".format(fp.gear.dw)
+        fp.transverse_pitch = "{}mm".format(fp.gear.pitch)
 
     def __getstate__(self):
         return None

pygears/involute_tooth.py

@@ -48,6 +48,8 @@ class InvoluteTooth():
         else:
             self.pressure_angle_t = self.pressure_angle
             self.m = self.m_n
+
+        self.pitch = self.m * np.pi
         self.c = self.clearance * self.m_n
         self.midpoint = [0., 0.]
         self.d = self.z * self.m
@@ -216,7 +218,7 @@ class InvoluteRack(object):
         if self.add_endings:
             ext1 = teeth[0] + np.array([0., a + b - pitch / 2])
             ext2 = teeth[-1] - np.array([0., a + b - pitch / 2])
-            teeth = [ext1.tolist(), ext1.tolist()] + teeth + [ext2.tolist(), ext2.tolist()]
+            teeth = [ext1.tolist(), ext1.tolist()] + teeth.tolist() + [ext2.tolist(), ext2.tolist()]
         else:
             teeth = [teeth[0].tolist()] + teeth.tolist() + [teeth[-1].tolist()]
         #teeth.append(list(teeth[-1]))