You don't really need a pattern for this unless you want a fancy one that looks like a snake or wiener dog. I'm sure there are patterns on line or in pattern books for those.

To make just a roll---=Measure your door and add 5 or 6 inches to the total. Cut a piece of sturdy fabric 8 inches x your measured length+ the extra. Sew the long end and reinforce it. You now have a 4 " tube. Sew one end closed again reinforcing it. Turn to the right side and push out the corners. Fill with non-clumping kitty litter to 1 inch of the top. Don't tamp it down. You don't want a solid lump so it won't conform to the door. Turn under 1/2 inch on remaining end and top stitch closed

I made some for DD and we used play sand.
Kathy G in MI

http://www.marthastewart.com/article/draft-dodger

I am SO making some of those! Martha Stewart used kitty litter made from recycled newspaper so there's no scent. Great idea!