3. Space Trusses Space truss – 3D truss, where connections are made through ball and socket joints. Simplest shape for a space truss is a tetrahedral shape – 4 triangles. We can use the same analysis techniques as we did for plane trusses, except that we must now meet the 3D equilibrium conditions. Method of Joints: This method is identical as for 2D, except that each force has 3 components and it is necessary to look at all three directions simultaneously. Method of Sections: This method is identical as for 2D. Note that each force has 3 components and it is necessary to look at all three directions simultaneously. Do not cut through more than six members, if possible! It is typically difficult to choose a moment axis that will eliminate all but one unknown. Therefore this method is not used very often.