Rules for constructing form diagram

[FlorisWL]

Do some extra research on general rules on constructing a form diagram, this is important for the tool to work at all times.

• [x] Define and document a clear set of rules, including a reference

[FlorisWL]

Constructing a force resultant: order doesn't matter

Constructing the form diagram (finding the unknown forces for a joint):

• Go clockwise.
• Regarding external forces: I think, acting towards the joint should be seen as positive. So always draw them as acting towards the joint; compressing instead of pulling if you will.

"The reason for here taking them in order, going around the joint in a clockwise direction, is to have the polygons for the various joints of such shape that they will fit together and form a stress diagram." (Wolfe, 1921)