Measuring surface form with a Fizeau interferometer typically requires a high-precision reference optic with the same form as the surface being tested. This approach works very well for flat or spherical surfaces but can be extremely challenging for measuring freeform or aspheric surfaces, which are increasingly deployed in today's sophisticated optical designs. ZYGO is redefining the use of computer-generated holograms (CGHs) with novel and unique alignment methods that make the measurement of complex surfaces easy, and ideally suited for production.