Dealing with irregular shapes is a common occurrence when building your van. Unless you have a box truck or step van, your vehicle has lots of curved walls, ribs, bolts, and other things you'll need to work around. There are a few ways to deal with these unusual shapes and creating pieces to fit them.
Ticking sticks
Use a ticking stick to recreate odd shapes on whatever board or other object you'll need to fit into that space. Essentially, you are creating a drawing of a large shape inside a small shape, and then using the small shape to recreate the large shape somewhere else.
Foil shape tracing
The aluminum foil solution works well for surfaces with odd shapes, such as when creating window coverings. Attach sheets of foil to the surface and to each other, conforming the foil tightly around the edges of the shape. Then, carefully remove the entire aluminum shape, and transfer it to your work surface. The aluminum foil will be the exact shape and size you need, so you can just trace around it on your new material. Then, recycle the foil!
Cardboard shape tracing
Similar to foil tracing, cardboard can be positioned, cut, and joined to trace shapes. It works well in cases where the cardboard can either lie flat against a surface or free-standing vertical. For example, you can use large cardboard pieces to find the shape of an opening when building a bulkhead or filling in a doorway. Place the cardboard roughly into position, and then trim it back or tape on other smaller pieces of cardboard until you get close enough to the edge you're tracing. When finished, you can use the cardboard as a template to cut your final material.
Wire tracing
Moderately stiff electrical wire or craft wire can be bent into shape to follow the curvature of a wall or other surface. You may need to use pliers to accurately bend the wire, depending on its stiffness.
Edge tracer tools
You can use an edge tracer tool to get the outline of a small shape.
