Dense 3D models of heritage buildings are difficult to consider directly for visual reproduction. Major ongoing efforts are made to produce tools to address the live rendering problem of huge 3D point clouds. Anyway, they often require an important computing power and renderings are tough to understand due to the amount of data. Thus, it is necessary to design new tools so that any user can easily see and understand the visual reproduction of a digitized heritage building. Toward that goal, we propose a new way to consider 3D point cloud slices in order to describe and show the heritage building in a web system. The methodology to design a web system of cultural mediation is presented, focusing on its genericity. It is applied to the Amiens cathedral and feedbacks of users are provided.