In this technical report, we present a detailed overview of PixelFlex, a multi-projector display system that combines multiple roughly aligned projectors into a unified highresolution display. We describe the current prototype, the automated calibration process, and two rendering algorithms that support interactive applications. The first rendering algorithm is a one-pass technique that assumes little or no optical projector distortions. It corrects for the linear shear distortions (keystoning) that result from casual projector alignment and non-orthonormal projection. The second rendering algorithm is a two-pass technique that corrects for both linear projection distortions and non-linear distortions introduced by non-planar display surfaces and projector lens distortion.