Ureña, CarlosGeorgiev, IliyanJakob, Wenzel and Hachisuka, Toshiya2018-07-012018-07-0120181467-8659https://doi.org/10.1111/cgf.13471https://diglib.eg.org:443/handle/10.1111/cgf13471We present a method for uniformly sampling points inside the projection of a spherical cap onto a plane through the sphere's center. To achieve this, we devise two novel area-preserving mappings from the unit square to this projection, which is often an ellipse but generally has a more complex shape. Our maps allow for low-variance rendering of direct illumination from finite and infinite (e.g. sun-like) spherical light sources by sampling their projected solid angle in a stratified manner. We discuss the practical implementation of our maps and show significant quality improvement over traditional uniform spherical cap sampling in a production renderer.Computing methodologiesRenderingRay tracingVisibility10.1111/cgf.1347113-20