Frames and machines differ from simple trusses in that:

Frames and machines are always larger than trusses.

Trusses are composed only of two$-$force members whereas frames and machines have one or more multiforce member.

Truss structures are always larger than frames and machines.

All frames and machines are statically indeterminate.

A multiforce member must have:

Forces applied at three or more points, or forces applied at two or more points and at least one couple applied.

At least one couple acting on it$.$

At least three applied forces and a couple acting on it$.$

At least four forces acting on it$.$