It is common to have Eq.(1) in a form where \mathbf{q}^m and \mathbf{Q}^{om} are, respectively, the member-end displacements and forces matching in direction with r and R. In such case, \mathbf{K} and \mathbf{R}^o can be obtained by direct summation of the members' matrices \mathbf{k}^m and \mathbf{Q}^{om} .
The advantages and disadvantages of the matrix stiffness method are compared and discussed in the flexibility method article.