Add flat-top style baseplates

The current design of the baseplates with a sharp edge at the top of the
base plates is not ideal for printability. Slicers try to approximate
this sharp edge with a thin perimeter line that is usually disjoint from
the perimeters at the grid intersections.  The end result is quite
uneven.

Introduce a new "top style" configuration option which defaults to
"sharp" - the current behavior.  An alternate "flattened" setting
removes two top two layers of the baseplate, leaving a flat surface with
a width of roughly two perimeter lines on top.  This is sliced much more
consistently and the printed result also looks a lot better.  The
functional impact of not having a sharp edge on top is neglible.

Author: Rahix

gridfinity-rebuilt-baseplate.scad

@@ -56,6 +56,9 @@ style_plate = 3; // [0: thin, 1:weighted, 2:skeletonized, 3: screw together, 4:
 // hole styles
 style_hole = 0; // [0:none, 1:countersink, 2:counterbore]
 
+// top style
+style_top = 0; // [0:sharp, 1: flattened]
+
 /* [Magnet Hole] */
 // Baseplate will have holes for 6mm Diameter x 2mm high magnets.
 enable_magnet = true;
@@ -69,7 +72,7 @@ hole_options = bundle_hole_options(refined_hole=false, magnet_hole=enable_magnet
 // ===== IMPLEMENTATION ===== //
 
 color("tomato")
-gridfinityBaseplate([gridx, gridy], l_grid, [distancex, distancey], style_plate, hole_options, style_hole, [fitx, fity]);
+gridfinityBaseplate([gridx, gridy], l_grid, [distancex, distancey], style_plate, hole_options, style_hole, style_top, [fitx, fity]);
 
 // ===== CONSTRUCTION ===== //
 
@@ -85,9 +88,10 @@ gridfinityBaseplate([gridx, gridy], l_grid, [distancex, distancey], style_plate,
  * @param sp Baseplate Style
  * @param hole_options
  * @param sh Style of screw hole allowing the baseplate to be mounted to something.
+ * @param style_top Style of the top edge of the baseplate. Can be 0 (sharp edge) or 1 (flattened for better printability).
  * @param fit_offset Determines where padding is added.
  */
-module gridfinityBaseplate(grid_size_bases, length, min_size_mm, sp, hole_options, sh, fit_offset = [0, 0]) {
+module gridfinityBaseplate(grid_size_bases, length, min_size_mm, sp, hole_options, sh, style_top, fit_offset = [0, 0]) {
 
     assert(is_list(grid_size_bases) && len(grid_size_bases) == 2,
         "grid_size_bases must be a 2d list");
@@ -99,6 +103,8 @@ module gridfinityBaseplate(grid_size_bases, length, min_size_mm, sp, hole_option
         "Must have positive x grid amount!");
     assert(grid_size_bases.y > 0 || min_size_mm.y > 0,
         "Must have positive y grid amount!");
+    assert(style_top >= 0 && style_top <= 1,
+        "style_top must be 0 or 1");
 
     additional_height = calculate_offset(sp, hole_options[1], sh);
 
@@ -213,6 +219,12 @@ module gridfinityBaseplate(grid_size_bases, length, min_size_mm, sp, hole_option
             translate([0, 0, additional_height/2])
             cutter_screw_together(grid_size.x, grid_size.y, length);
         }
+
+        if (style_top == 1) {
+            translate([0, 0, baseplate_height_mm])
+            // Cut off 2 layers from the top so the slicer can generate 2 perimeters side-by-side.
+            cube([size_mm[0] + 2, size_mm[1] + 2, LAYER_HEIGHT*4], center=true);
+        }
     }
 }