In this paper we present smARt.assembly - a projection-based augmented reality (AR) assembly assistance system for industrial applications. Our system projects digital guidance information in terms of picking information and assembly data into the physical workspace of a user. By using projections, we eliminate the use of smart glasses that have drawbacks such as a limited field of view or low wearing comfort. With smARt.assembly, users are able to assemble products without previous knowledge and without any other assistance.