Intuitive creation of landscape elements

The intuitive creation techniques studied up to now (drawing, sculpture, transfer) concerned isolated objects: how can they be extended to the creation of a virtual world whose elements are too numerous to be manipulated one by one, and for which a certain number of laws - biological, geological or statistical, for example - must be maintained? This lecture presented and illustrated several scaling methodologies, such as the combination of drawing and procedural modeling to create clouds, progressive design at different resolutions to create trees, silhouette drawing to sculpt mountains, and the use of a painting metaphor to quickly instantiate the elements of a virtual world.