Carving shapes from blocks of foam can be a quick and effective way tocreate large structural pieces. Heads are where I most commonly usecarved foam. There's a separate page onfoam heads.
A rabbit head carved by Farallon Seal. The detritus gives some idea of how messy this process is! I recommend laying out a large dropcloth to aid in cleaning up after the carving is finished.
Carving foam is relatively easy. I recommend working with an electriccarving knife. See the Foam Carving Tools page.
The general idea is to start with your block of foam and carve it down into the desired shape. It helps to sketch on the foam with a marker to visualize the goal relative to the block. Start by making major cuts to rough out the overall shape; then go in and add details and smaller contours. For a head, be sure to hollow out the inside early on so that you can see how it will sit on your head. More detail on this process is in the Step-by-Step Foam Carving Description page.
