A new radiosity approach for regular objects: application to ruled surfaces

Abstract

This paper introduces a new approach in the radiosity method. The main principle applied here, is the improvement of form factor computation by the knowledge of the model properties. More precisely, if surfaces describing a scene are"regular", the values of the form factor and its"derivatives" between any patch B and a patch A intervening in the meshing of a given surface, enable us to evaluate (with a required precision) the form factors values between B and the neighboring patches of A. We will also show that the mathematical relation we have obtained, 1) is especially efficient with ruled surfaces, 2) significantly decreases the computation time, 3) is well-adapted to refinement or subdivision techniques and 4) gives us an interesting variety of surfaces. Calculation times are equivalent to those obtained with a projective method (hemi-cube for example) but with an efficient control of the generated errors.