diff --git a/src/half_edge_AS.c b/src/half_edge_AS.c
index 64ca5bf..8cbf293 100644
--- a/src/half_edge_AS.c
+++ b/src/half_edge_AS.c
@@ -289,7 +289,7 @@ static void assemble_HE_stage1(obj_items const * const raw_obj,
 		vc++;
 	}
 
-	while (raw_obj->bez[bzc]) {
+	while (raw_obj->bez && raw_obj->bez[bzc]) {
 		uint32_t i = 0;
 		vector *bez_vec = NULL;