For us to use the same identical transformation matrix used for stress, the equation shown is set up to transform 1/2 of the *engineering shear* strain. Although this is explained in the textbook, you do not need to worry about it because this page, and CADEC in general, takes care of that extra step. This means that you enter *engineering shear* strain (denoted by ) in *laminate* c.s. and get the resulting *engineering shear* strain in *lamina* c.s.

If you want the opposite transformation (from lamina to laminate c.s.) simply enter minus the angle. This is easy to understand if you consider Figure 6.3.