diff --git a/libraries/physics/src/CharacterController.cpp b/libraries/physics/src/CharacterController.cpp
index cee0e6a1fa..b716d5c0d1 100755
--- a/libraries/physics/src/CharacterController.cpp
+++ b/libraries/physics/src/CharacterController.cpp
@@ -121,6 +121,8 @@ void CharacterController::setDynamicsWorld(btDynamicsWorld* world) {
             _dynamicsWorld->addAction(this);
             // restore gravity settings because adding an object to the world overwrites its gravity setting
             _rigidBody->setGravity(_currentGravity * _currentUp);
+            // set flag to enable custom contactAddedCallback
+            _rigidBody->setCollisionFlags(btCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK);
             btCollisionShape* shape = _rigidBody->getCollisionShape();
             assert(shape && shape->getShapeType() == CONVEX_HULL_SHAPE_PROXYTYPE);
             _ghost.setCharacterShape(static_cast<btConvexHullShape*>(shape));
@@ -294,14 +296,14 @@ void CharacterController::playerStep(btCollisionWorld* collisionWorld, btScalar
 
             // compute the angle we will resolve for this dt, but don't overshoot
             float angle = 2.0f * acosf(qDot);
-            if ( dt < _followTimeRemaining) {
+            if (dt < _followTimeRemaining) {
                 angle *= dt / _followTimeRemaining;
             }
-            
+
             // accumulate rotation
             deltaRot = btQuaternion(axis, angle);
             _followAngularDisplacement = (deltaRot * _followAngularDisplacement).normalize();
-            
+
             // in order to accumulate displacement of avatar position, we need to take _shapeLocalOffset into account.
             btVector3 shapeLocalOffset = glmToBullet(_shapeLocalOffset);
 
diff --git a/libraries/physics/src/PhysicsEngine.cpp b/libraries/physics/src/PhysicsEngine.cpp
index 66a4edb486..eca8324e9f 100644
--- a/libraries/physics/src/PhysicsEngine.cpp
+++ b/libraries/physics/src/PhysicsEngine.cpp
@@ -18,6 +18,7 @@
 #include <PerfStat.h>
 #include <PhysicsCollisionGroups.h>
 #include <Profile.h>
+#include <BulletCollision/CollisionShapes/btTriangleShape.h>
 
 #include "CharacterController.h"
 #include "ObjectMotionState.h"
@@ -26,6 +27,25 @@
 #include "ThreadSafeDynamicsWorld.h"
 #include "PhysicsLogging.h"
 
+
+static bool flipNormalsMyAvatarVsBackfacingTriangles( btManifoldPoint& cp,
+        const btCollisionObjectWrapper* colObj0Wrap, int partId0, int index0,
+        const btCollisionObjectWrapper* colObj1Wrap, int partId1, int index1) {
+    if (colObj1Wrap->getCollisionShape()->getShapeType() == TRIANGLE_SHAPE_PROXYTYPE) {
+        auto triShape = static_cast<const btTriangleShape*>(colObj1Wrap->getCollisionShape());
+        const btVector3* v = triShape->m_vertices1;
+        btVector3 faceNormal = colObj1Wrap->getWorldTransform().getBasis() * btCross(v[1] - v[0], v[2] - v[0]);
+        float nDotF = btDot(faceNormal, cp.m_normalWorldOnB);
+        if (nDotF <= 0.0f) {
+            faceNormal.normalize();
+            // flip the contact normal to be aligned with the face normal
+            cp.m_normalWorldOnB += -2.0f * nDotF * faceNormal;
+        }
+    }
+    // return value is currently ignored but to be future-proof: return false when not modifying friction
+    return false;
+}
+
 PhysicsEngine::PhysicsEngine(const glm::vec3& offset) :
         _originOffset(offset),
         _myAvatarController(nullptr) {
@@ -68,6 +88,9 @@ void PhysicsEngine::init() {
         // in order for its broadphase collision queries to work correctly. Look at how we use
         // _activeStaticBodies to track and update the Aabb's of moved static objects.
         _dynamicsWorld->setForceUpdateAllAabbs(false);
+
+        // register contact filter to help MyAvatar pass through backfacing triangles
+        gContactAddedCallback = flipNormalsMyAvatarVsBackfacingTriangles;
     }
 }