Bubbles fixes

- older versions of openscad don't honor let();
- limit the minimum sphere fragment size to 0.5, that makes no visible
  difference with 0.2 mm layers but dramatically reduces the rendering time.

Signed-off-by: Ivan Kokshaysky <ink@rc.ru>

1 files changed, 5 insertions, 3 deletions

diff --git a/bubbles.scad b/bubbles.scad
index 2f25938..c586736 100644
--- a/bubbles.scad
+++ b/bubbles.scad
@@ -1,11 +1,13 @@
  module bubbles(size,d=1.2,s=1.8) {
   maxr=max(d/2,size[1]);
   scl = [ d/2/maxr, size[1]/maxr, d/2/maxr ];
   nx = floor((size[0]-2*d)/s); sx = s*nx; x0=(size[0]-sx)/2;
   nz = floor((size[2]-2*d)/s); sz = s*nz; z0=(size[2]-sz)/2;
-  for(iz=[0:nz]) let(z=z0+s*iz) {
-   for(ix=[0:iz%2?nx-1:nx]) let(x=x0+(iz%2?s/2:0)+s*ix) {
-    translate([x,0,z]) scale(scl) sphere(r=maxr,$fn=30);
+  for(iz=[0:nz]) {
+   z=z0+s*iz;
+   for(ix=[0:iz%2?nx-1:nx]) {
+    x=x0+(iz%2?s/2:0)+s*ix;
+    translate([x,0,z]) scale(scl) sphere(r=maxr,$fs=0.5);
    }
   }
  }