We propose a framework based on integral geometry that makes it possible to express and solve most geometrical sunlighting problems within CAD systems: the direct problems for assessing sunlighting in a scene and the inverse ones for achieving sunlighting constraints in a design context. The heart of our method is the sunlighting volume that we denote Pi(P, T). We describe this notion and we show how to implement it in an architectural and urban design process. (C) 2004 Elsevier B.V. All rights reserved.