Space truss problems can be solved by choosing a joint with only three unknown member forces and one or more known load forces. The forces at the joint are summed in all three directions which will produce three equations and three unknowns.
= 0 ΣFy
= 0 ΣFz
The method of joints is usually the easiest method since the moment equilibrium equations are difficult to apply in 3D.
Vector notation should be used with 3-D problems because of the complexity of 3-D geometry.