Modeling virtual worlds remains an open problem in computer graphics. A perennial and challenging problem is the modeling of complex, large natural scenes made of multiple materials with a high level of detail featuring scenic landforms such as cliffs with overhangs, waterfalls or glaciers. In this thesis, we address the problem of modeling virtual worlds using implicit surfaces that represent complex shapes using compact equations, but traditionally prove to be more difficult to control and visualize. Multiple research directions will be considered: 1) building a set of primitives and operators, especially adapted for the animation of fluids; 2) developing control tools to sculpt and animate the shapes generated by our model; 3) investigating procedural or physically inspired methods for generating realistic landforms, adapted to the natural phenomena.