partly sort the polygon order of the EngraveCutter by size

add support grids to bigger inner holes


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@653 bbaffbd6-741e-11dd-a85d-61de82d9cad9

src/pycam/PathGenerators/EngraveCutter.py

@@ -119,7 +119,13 @@ class EngraveCutter:
             elif (area2 < 0) and (area1 > 0):
                 return 1
             else:
-                return 0
+                # do a "relaxed" sorting by size
+                if abs(area1) < 2 * abs(area2):
+                    return -1
+                elif abs(area2) < 2 * abs(area1):
+                    return 1
+                else:
+                    return 0
         line_groups.sort(cmp=polygon_priority)
 
         # process the final layer with a drop cutter

src/pycam/Toolpath/SupportGrid.py

@@ -161,7 +161,10 @@ def get_support_distributed(model, z_plane, average_distance,
     # minimum required distance between two bridge start points
     avoid_distance = 1.5 * (abs(length) + thickness)
     for polygon in model.get_polygons():
-        if not polygon.is_outer():
+        # no grid for _small_ inner polygons
+        # TODO: calculate a reasonable factor (see below)
+        if not polygon.is_outer() \
+                and (abs(polygon.get_area()) < 25000 * thickness ** 2):
             continue
         lines = polygon.get_lines()
         poly_lengths = polygon.get_lengths()