Partial Node Connection for RigidElement (MPC version)

[epsi1on]

Think of this model

if we use tetrahedron, then should fix rotation for all nodes as tetrahedron cannot handle nodal rotation DoF. And if we want to connect nodes at the tip of beam with a RigidElement and apply a force to center node

Then the rigid element will not rotate because rotation DoF of all connected nodes are fixed. Hence there should be feature so that RigidElement can handle partial node connection, then we can set it to strainght move only (DX, DY and DZ) for above example.

[epsi1on]

in order to reduce complexity of features and codes, this feature is not implemented. A workaround for such model is to release 3 rotation DoFs of 5 end nodes and let them rotate as they are connected to a rigid element