diff --git a/apps/openmw/mwphysics/actor.cpp b/apps/openmw/mwphysics/actor.cpp
index 5167f6ef0..e0edd515d 100644
--- a/apps/openmw/mwphysics/actor.cpp
+++ b/apps/openmw/mwphysics/actor.cpp
@@ -35,6 +35,7 @@ Actor::Actor(const MWWorld::Ptr& ptr, osg::ref_ptr<const Resource::BulletShape>
     }
     else
         mShape.reset(new btBoxShape(toBullet(mHalfExtents)));
+    mConvexShape = static_cast<btConvexShape*>(mShape.get());
 
     mCollisionObject.reset(new btCollisionObject);
     mCollisionObject->setCollisionFlags(btCollisionObject::CF_KINEMATIC_OBJECT);
diff --git a/apps/openmw/mwphysics/actor.hpp b/apps/openmw/mwphysics/actor.hpp
index 9c0144b9d..a640640e2 100644
--- a/apps/openmw/mwphysics/actor.hpp
+++ b/apps/openmw/mwphysics/actor.hpp
@@ -12,6 +12,7 @@
 class btCollisionWorld;
 class btCollisionShape;
 class btCollisionObject;
+class btConvexShape;
 
 namespace Resource
 {
@@ -61,6 +62,8 @@ namespace MWPhysics
             return mInternalCollisionMode;
         }
 
+        btConvexShape* getConvexShape() const { return mConvexShape; }
+
         /**
          * Enables or disables the *external* collision body. If disabled, other actors will not collide with this actor.
          */
@@ -153,6 +156,7 @@ namespace MWPhysics
         bool mWalkingOnWater;
 
         std::auto_ptr<btCollisionShape> mShape;
+        btConvexShape* mConvexShape;
 
         std::auto_ptr<btCollisionObject> mCollisionObject;
 
diff --git a/apps/openmw/mwphysics/physicssystem.cpp b/apps/openmw/mwphysics/physicssystem.cpp
index 6d7daa3b8..0884798df 100644
--- a/apps/openmw/mwphysics/physicssystem.cpp
+++ b/apps/openmw/mwphysics/physicssystem.cpp
@@ -239,7 +239,7 @@ namespace MWPhysics
     public:
         static osg::Vec3f traceDown(const MWWorld::Ptr &ptr, Actor* actor, btCollisionWorld* collisionWorld, float maxHeight)
         {
-            osg::Vec3f position(ptr.getRefData().getPosition().asVec3());
+            osg::Vec3f position(actor->getCollisionObjectPosition());
 
             ActorTracer tracer;
             tracer.findGround(actor, position, position-osg::Vec3f(0,0,maxHeight), collisionWorld);
diff --git a/apps/openmw/mwphysics/trace.cpp b/apps/openmw/mwphysics/trace.cpp
index feda68ca5..10d22ec7f 100644
--- a/apps/openmw/mwphysics/trace.cpp
+++ b/apps/openmw/mwphysics/trace.cpp
@@ -4,7 +4,6 @@
 
 #include <BulletCollision/CollisionDispatch/btCollisionWorld.h>
 #include <BulletCollision/CollisionShapes/btConvexShape.h>
-#include <BulletCollision/CollisionShapes/btCylinderShape.h>
 
 #include "collisiontype.hpp"
 #include "actor.hpp"
@@ -106,12 +105,7 @@ void ActorTracer::findGround(const Actor* actor, const osg::Vec3f& start, const
     newTraceCallback.m_collisionFilterMask = actor->getCollisionObject()->getBroadphaseHandle()->m_collisionFilterMask;
     newTraceCallback.m_collisionFilterMask &= ~CollisionType_Actor;
 
-    btVector3 halfExtents = toBullet(actor->getHalfExtents());
-
-    halfExtents[2] = 1.0f;
-    btCylinderShapeZ base(halfExtents);
-
-    world->convexSweepTest(&base, from, to, newTraceCallback);
+    world->convexSweepTest(actor->getConvexShape(), from, to, newTraceCallback);
     if(newTraceCallback.hasHit())
     {
         const btVector3& tracehitnormal = newTraceCallback.m_hitNormalWorld;