Master’s thesis: Raytracing with Distance Fields

Conzept

In recent years, distance fields have already been used by companies in the entertainment industry. This geometry representation is used for the accelerated calculation of shadow effects or for the generation of varying detailed geometries. This paper deals with the creation of high-quality and robust distance fields using distance functions, for which a distance function catalog with operation and geometry definitions has been compiled. It also contains a summary of basic techniques for calculating images from distance fields. These are based on the concept of calculating intersection points using raymarching algorithms, for which a further acceleration extension (restart-over-relaxation sphere tracing) is presented. To accelerate the lighting calculation, approximations for complex lighting effects (soft shadows, ambient occlusion and subsurface scattering) are presented, which work on the basis of the distance values contained in the distance fields.

To evaluate these techniques and the creation of distance functions, prototypes of a distance field editor and ray tracer were implemented. This evaluation has shown that the creation of distance functions is not intuitive and requires advanced mathematical knowledge. Nevertheless, they have shown great potential due to the power of the procedural description and their low memory requirements. Using the techniques implemented in the distance field ray tracer, optically usable results could be achieved, which confirmed the short runtimes for the approximations of the illumination effects. However, these approximations do not provide realistic results, which means that they have only proven to be of limited use.

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