Abstract: In this paper we describe a method for computing approximate results of boolean operations (union, intersection, difference) applied to free-form solids bounded by multiresolution subdivision surfaces. We present algorithms for generating a control mesh for a multiresolution surface approximating the result, optimizing the parameterization of the new surface with respect to the original surfaces, and fitting the new surface to the geometry of the original surfaces. Our algorithms aim to minimize the size and optimize the quality of the new control mesh. The original control meshes are modified only in a neighborhood of the intersection. While the main goal is to obtain approximate results, high-accuracy approximations are also possible at additional computational expense, if the topology of the intersection curve is resolved correctly.