3D lettering can be made out of foam, along with other materials. The sign examples below are made with HDU - High Density Urethane - Sign Foam which must be hand carved then coated with many layers of paint to obtain the glossy finish. HDU Sign Foam can last for 10 years, indoor or out, against deterioration, warping, and cracking. It is 100% waterproof, unaffected by temperature and will not rot or decompose. High Density Urethane material is preferable on most projects, and is a must on outdoor sign projects. HDU will not warp, crack, or bow like solid wood when exposed to the elements. It is slightly lighter that wood, which might be a consideration for a suspended sign. HDU Sign Foam can be seamlessly laminated together to create any size shape or form.