Here's what I would Do.. Similar to Ray, I would Break it up to ,not just Triangles, but other figures too. say a Star, you could break it up into 5 (im guessin
) triangular prisms and the remaining part would become a pentagon(again, Im guessing
).. in the end add them up...
or just as Ray said Use CAD. or ask someone who knows how to.
hope it helps