Projection mapping is a group of techniques for project- ing imagery onto physical three-dimensional objects in order to augment the object or space with digital content. Most projection mapping experiences and events are non-interactive, partly because of the many inherent design problems in designing for interaction is such situations. This article explores one approach to this tricky issue by analysing a group of four interac- tive mixed reality experiences that combine projection mapping with camera-based interaction techniques. The approaches used are described, and their deploy- ment in a variety of situations is analysed using engage- ment and play theories. The works suggest that some projection mapping techniques can be used in the service of creating engaging interactive exhibits and installations, but that the effectiveness of the approach relies on it placing the experience and interactions clearly in our own physical world, rather than behind a screen or in an artificial image space.
