diff --git a/cesium-integration.md b/cesium-integration.md
index 66d2bb0..7a9d397 100644
--- a/cesium-integration.md
+++ b/cesium-integration.md
@@ -57,9 +57,10 @@ Cesium examples:
 * Tooltips?
 
 Notes
- * Cesium places the 2D GeoJSON on the terrain according following rules:
+ * Cesium places the 2D GeoJSON on the terrain according to following rules:
   * Vertexes are precisely placed on the terrain
   * Segments go straight (in 3D) between the 2 Vertexes
+  * Heights must be manually set to have a 3D GeoJSON.
 
 ## Share edit
 Idea: use cesium picking information to get the coordinates in 3D. and send them back to the traditionnal transactional webservice