diff --git a/src/engine/InterestManagement/Terrain.java b/src/engine/InterestManagement/Terrain.java
index 4872e3fe..9721afac 100644
--- a/src/engine/InterestManagement/Terrain.java
+++ b/src/engine/InterestManagement/Terrain.java
@@ -113,7 +113,7 @@ public class Terrain {
 
         // Blend between heights
 
-        return interpolatedChildHeight + parentZone.worldAltitude * (1 - terrainZone.terrain.terrainBlend(terrainLoc));
+        return interpolatedChildHeight + interpolatedParentTerrainHeight * (1 - terrainZone.terrain.terrainBlend(terrainLoc));
 
     }