Soot particles can be formed in hydrocarbon flames as a result of an inefficient combustion process. The particles are near-spherical, and at later stages in the soot growth process, they form chainlike sparse aggregates. When applying optical diagnostic methods, this aggregation influences the evaluation of soot properties based on assumptions of isolated particles. In this paper an efficient and accurate method for calculating scattering of light from these structures is presented. The method can handle aggregates with several hundred subparticles with no restrictions on shape, internal structure, or coagulation of the subparticles. The basic idea is that the induced dipole moments of the subparticles are determined from the solution of a quasi-static problem that can be solved with high accuracy by, e.g., the finite element method.