Preparation 3

Modify plans to suit your design.

Basically this means to markup your plans with whatever design you decided on.  It is important that you put the correct amount of seam allowances.

 So lets assume you want to built the following rev sail.

The first thing you need to do is modify your Rev plans to include the seam allowances for the green/blue joint.

The right line tells you where the green will stop, and the left line tells you where the blue will stop.