Abstract: Systems and methods for simulating illumination patterns on target surfaces in a space are disclosed. The system includes an input component and a simulation component. The input component receives a sampling angular range, a sampling polygon density, and a sampling polygon type. The simulation component traces sampling rays according to the sampling angular range and the sampling polygon density and type within a sampling range. The simulation component can further (1) generate an initial illumination pattern with a plurality of sampling polygon projections on the target surface; (2) assign the same value of an attribute in the sampling polygon projections defined by sampling rays through substantially the same route from the light source to the target surface; and (3) adjust the value of the attribute in the sampling polygon projection defined by sampling rays from different routes by interpolation.