diff --git a/serre-tringle.scad b/serre-tringle.scad
index 3aec893..1afdfc4 100644
--- a/serre-tringle.scad
+++ b/serre-tringle.scad
@@ -10,6 +10,9 @@ $radial_indent = 1;
 $slack = 0.1;
 $mini_slack = 0.001;
 
+// rendering precision
+$fn = $preview ? 32 : 64;
+
 // base
 difference() {
     cylinder($length_base, $diameter_z / 2, $diameter_z / 2);
diff --git a/serre-tringle.stl b/serre-tringle.stl
index 6ce9ba8..760061c 100644
Binary files a/serre-tringle.stl and b/serre-tringle.stl differ