diff --git a/man/qbsp.1 b/man/qbsp.1
index 54a61d02..887d2572 100644
--- a/man/qbsp.1
+++ b/man/qbsp.1
@@ -154,7 +154,9 @@ What entity you want the external map to turn in to.
 You can use internal qbsp entity types such as "func_detail",
 or a regular bmodel classname like "func_wall" or "func_door". 
 .IP "\fB_external_map_angles\fP"
-Rotation for the prefab, "pitch yaw roll" format. Negative pitch is down.
+Rotation for the prefab, "pitch yaw roll" format.
+Assuming the exernal map is facing the +X axis, positive pitch is down.
+Yaw of 180, for example, would rotate it to face -X.
 .IP "\fB_external_map_angle\fP"
 Short version of "_external_map_angles" for when you want to specify just a yaw rotation.
 .IP "\fB_external_map_scale\fP"