diff --git a/fed/mosaic-application/src/main/java/org/eclipse/mosaic/fed/application/ambassador/simulation/perception/index/providers/WallTree.java b/fed/mosaic-application/src/main/java/org/eclipse/mosaic/fed/application/ambassador/simulation/perception/index/providers/WallTree.java
index 025505f24..833cecf8a 100644
--- a/fed/mosaic-application/src/main/java/org/eclipse/mosaic/fed/application/ambassador/simulation/perception/index/providers/WallTree.java
+++ b/fed/mosaic-application/src/main/java/org/eclipse/mosaic/fed/application/ambassador/simulation/perception/index/providers/WallTree.java
@@ -52,7 +52,7 @@ public void initialize() {
                         wall.getFromCorner().getCartesianPosition().toVector3d(),
                         wall.getToCorner().getCartesianPosition().toVector3d()
                 ));
-                if (wall.length > maxWallLength) {
+                if (wall.getLength() > maxWallLength) {
                     maxWallLength = wall.getLength();
                 }
             }