const int kSize = 3*m_nodes.size();
	ublas::generalized_vector_of_vector<btScalar, ublas::row_major, ublas::vector<ublas::compressed_vector<btScalar> > > RKR_1(kSize, kSize);
	ublas::generalized_vector_of_vector<btScalar, ublas::row_major, ublas::vector<ublas::compressed_vector<btScalar> > > RK(kSize, kSize);

	for(int i=0; i<m_tetrahedrons.size(); ++i)
	{
		btTetrahedron* t = m_tetrahedrons[i];
		t->computeCorotatedStiffness();

		for(unsigned int j=0; j<12; ++j)
			for(unsigned int k=0; k<12; ++k)
			{
				RKR_1(t->getGlobalIndex(j), t->getGlobalIndex(k)) += t->getCorotatedStiffness0(j, k);
				RK(t->getGlobalIndex(j), t->getGlobalIndex(k)) += t->getCorotatedStiffness1(j, k);
			}
	}

	m_RKR_1 = RKR_1;
	m_RK = RK;