diff --git a/OpenSim/Region/Physics/UbitOdePlugin/OdeScene.cs b/OpenSim/Region/Physics/UbitOdePlugin/OdeScene.cs
index a554897e53..f3ac3ca3c1 100644
--- a/OpenSim/Region/Physics/UbitOdePlugin/OdeScene.cs
+++ b/OpenSim/Region/Physics/UbitOdePlugin/OdeScene.cs
@@ -1027,7 +1027,7 @@ namespace OpenSim.Region.Physics.OdePlugin
                                     {
                                         d.AABB aabb;
                                         d.GeomGetAABB(g2, out aabb);
-                                        float tmp = vtmp.Z - sz * .25f;
+                                        float tmp = vtmp.Z - sz * .18f;
 
                                         if (aabb.MaxZ < tmp)
                                         {
@@ -1057,7 +1057,7 @@ namespace OpenSim.Region.Physics.OdePlugin
                                     {
                                         d.AABB aabb;
                                         d.GeomGetAABB(g1, out aabb);
-                                        float tmp = vtmp.Z - sz * .25f;
+                                        float tmp = vtmp.Z - sz * .18f;
 
                                         if (aabb.MaxZ < tmp)
                                         {