This is how I layout and cut out mine. I would be interested in seeing how you do yours.
I am cutting out a four season tarp with doors using a template, sharpie, and a sharp pair of scissors.
This tarp is partially based on the designs found at DIY Gear Supply here http://www.backwoodsdaydreamer.com/w...inter-Tarp.jpg // I used the spreadsheet found here http://www.hammockforums.net/forum/s...ve+spreadsheet to calculate the catenary curves. The curve calculator was required due to changes made in the tie-out point locations.
30 yards of seconds* sil-nylon from Noah Lamport http://www.noahlamport.com/
When ordering from this vendor you need to be sure to ask them to take the fabric off the roll to save you some shipping cost.
*(no noticeable flaws in this fabric or the coating)
The template is made from foam core board from the Dollar Store.