Monolith's Mike Dassault is leaving that company for the greener pastures of fellow Seattle developers Valve. Dassault was a key figure in the development of Monolith's Lith Tech 3D engine technology, and will continue to devote his energies towards 3D engine design for an unannounced Valve project. "[Mike] has helped to build a great and highly skilled engine team, and his personal efforts have been nothing short of spectacular over the last few years," said Monolith CEO Jason Hall in a farewell message.