Worm Farm: A CAD Adventure

Build a little farm for an articulated worm. Start with a rake: a handle, a bar, a row of downward teeth. Hollow out a mushroom house, grow a fence, assemble a tractor with spinning wheels and snap-on rivets, then build a captive ball joint that lets the worm really bend. Finally bring the farm together.

Each chapter introduces one new idea, asks you to predict a change, and gives you a complete model to open. You can point at a part before learning its code name. Small fit samples come before whole mechanisms. Illustrations show the actual CAD geometry.

Read in order. Use the language reference as a dictionary when a word is unfamiliar. A model that renders is a starting point: inspect its parts, run its checks, and try a small printed sample before making the whole toy. Ask an adult to help with printing and small parts.