I noticed a lot of new threads lately from folks who are making a hex tarp with cat cut edges. One of the biggest obstacles is the cat cut. Wouldn't it be nice to draw a cat cut on a piece of cardboard or other stock and use it for ALL SIX SIDES! Well, here is a spreadsheet to figure that out.
Just enter the first 3 numbers in the first column.
1. Ridgeline length plus seam allowance (in.)
2. Half width plus seam allowance (in.)
3. Unit weight of fabric (oz/sy)
The graph is a picture of the cuts you need to make from the total length of raw fabric. Please excuse my feeble attempt to draw the cat curves with my mouse. They are the light weight lines on the graph. The heavy diagonal lines are the theoretical edges without the cat cuts.
I hope this attached spreadsheet is downloadable and can make your DIY experience a bit better.