diff --git a/vcg/space/rect_packer.h b/vcg/space/rect_packer.h
index e793b85e..ce2baef9 100644
--- a/vcg/space/rect_packer.h
+++ b/vcg/space/rect_packer.h
@@ -27,6 +27,7 @@
 #include <assert.h>
 #include <algorithm>
 #include <vector>
+#include <ctime>
 #include <vcg/space/point2.h>
 #include <vcg/math/similarity2.h>