In one embodiment, a method includes accessing a first distortion definition for a first color component of a collection of pixels and a second distortion definition for a second color component of the collection of pixels; casting, from a viewpoint in a 3D space, a first bundle of rays for the first color component in accordance with the first distortion definition; computing a first set of intersection locations between the cast first bundle of rays and an object in the 3D space; determining, based on the first and second distortion definitions, that a difference between distortions of the first and second color components satisfies a predetermined threshold; estimating, using the first set of intersection locations, a second set of intersection locations on the object for the second color component; and determining color values for the collection of pixels based on the first and second sets of intersection locations.