The Choprical Fish: a Human Powered Party Bike

Step 3 Prepare full-scale drawing of frame for welding.

I got large craft paper from a packaging store and began to draw out the curves of my frame. I started with the crucial points: the bottom bracket, the centers of the front and rear wheels, and the seat. These are the parts that affect how your bicycle will ride.

If you don't have direct experience with designing bikes, I recommend copying the geometry on a bike you like riding, and making, perhaps minor changes to crucial elements like the head tube angle.