Soundpainting is the multidisciplinary live composing sign language, created by New-York composer Walter Thompson since 1974. It allows a composer-conductor (the soundpainter), to instantly and precisely communicate with an ensemble of performers. In reaction to a sign, a performer is about to propose material for the composition, that the soundpainter is going to capture, enrich, and compose with by sending new indications. Soundpainting is a powerful tool for artistic education and performance.