diff --git a/util/Transform.cc b/util/Transform.cc
index 7d0978a..1e9e6ed 100644
--- a/util/Transform.cc
+++ b/util/Transform.cc
@@ -29,8 +29,8 @@ void Transform::rotate(double angle, double xv, double yv, double zv)
     Vector l(xv, yv, zv);
     l.normalize();
 
-    double c = cos(angle);
-    double s = sin(angle);
+    double c = cos(M_PI * angle / 180.0);
+    double s = sin(M_PI * angle / 180.0);
 
     double lx2 = l[0] * l[0];
     double ly2 = l[1] * l[1];