Abstract: We present an out-of-core mesh decimation algorithm that is able to handle input and output meshes of arbitrary size. The algorithm reads the input from a data stream in a single pass and writes the output to another stream while using only a fixed-sized in-core buffer. By applying randomized multiple choice optimization, we are able to use incremental mesh decimation based on edge collapses and the quadric error metric. The quality of our results is comparable to state-of-the-art high-quality mesh decimation schemes (which are slower than our algorithm) and the decimation performance matches the performance of the most efficient out-of-core techniques (which generate meshes of inferior quality).