diff --git a/src/rodassembler.cc b/src/rodassembler.cc
index 1df607afca466e926a1135bfb9c2111bf4487948..360beef7d4f9943f9750f50956c7a53d602f94de 100644
--- a/src/rodassembler.cc
+++ b/src/rodassembler.cc
@@ -210,7 +210,7 @@ getStress(const std::vector<RigidBodyMotion<3> >& sol,
 
 template <class GridType>
 Dune::FieldVector<double,3> RodAssembler<GridType>::
-getResultantForce(const BoundaryPatch<GridType>& boundary, 
+getResultantForce(const LevelBoundaryPatch<GridType>& boundary, 
                   const std::vector<RigidBodyMotion<3> >& sol,
                   Dune::FieldVector<double,3>& canonicalTorque) const
 {
@@ -274,7 +274,7 @@ getResultantForce(const BoundaryPatch<GridType>& boundary,
             // the canonical basis of R^3
 
             FieldMatrix<double,3,3> orientationMatrix;
-            sol[indexSet.template subIndex<1>(*eIt,nIt->numberInSelf())].q.matrix(orientationMatrix);
+            sol[indexSet.subIndex(*eIt,nIt->indexInInside())].q.matrix(orientationMatrix,1);
             
             orientationMatrix.umv(localStress, canonicalStress);