diff --git a/src/primitives.cc b/src/primitives.cc
index 4aeec532..9fea2e9b 100644
--- a/src/primitives.cc
+++ b/src/primitives.cc
@@ -194,6 +194,7 @@ void register_builtin_primitives()
 */
 int get_fragments_from_r(double r, double fn, double fs, double fa)
 {
+	if (r < GRID_FINE) return 0;
 	if (fn > 0.0)
 		return (int)fn;
 	return (int)ceil(fmax(fmin(360.0 / fa, r*M_PI / fs), 5));