The analysis engine uses classical matrix structural analysis techniques in which element stiffness matrices and element load vectors are formed and then summed into system responses. Numerous transformations are applied to both the element stiffness and load matrices in order to realize such effects as force releases and master-slave constraints. It uses an efficient active-matrix block equation solver to solve for translational and rotational unknowns; boundary conditions are implemented by eliminating equations at the system level. The analysis package uses a right-handed global X-Y-Z coordinate system in which the positive Y-axis is vertical.