diff --git a/fgd/point/env/env_cubemap.fgd b/fgd/point/env/env_cubemap.fgd
index e41d732ab..0047bbb97 100644
--- a/fgd/point/env/env_cubemap.fgd
+++ b/fgd/point/env/env_cubemap.fgd
@@ -21,6 +21,7 @@
 		10: "512x512"
 		11: "1024x1024"
 		12: "2048x2048"
+		13: "4096x4096"
 		]
 
 	sides(sidelist) : "Brush faces" : : "(Optional) Brushes faces to directly attach to the env_cubemap. Press Pick then click on faces in the 3D View to select them. Use CTRL while clicking to add or remove from the selection."