The composite image as it is used today since the emergence of mediatic image, and in particular since the propagation of digital technologies applied to images, is defined as a homogeneous visual object composed from heterogeneous elements. However, in this article, the idea of a compositing carried out in real time is questioned. In this particular type of compositing, unlike a combination made from sources which are not co-present, there is constant coexistence of heterogeneous elements assembled, creating an experience of the composite which can at any time become an image (capture of screen or photographic or videographic). It is therefore no longer just a question of a composite image, but of the experience of the composite. To support this point, this article proposes to compare three types of projections that produce composite in real space, creating a mixed reality, to then come back to the notion of composite and identify its material character. Then is analyzed, through an analogy with the industrial technique of projection molding, the way in which the nesting of images occurs in space.