Hardware accelerated ray tracing of particle systems

Abstract: Background. Particle systems are a staple feature of most modern renderers. There are several technical challenges when it comes to rendering transparent particles. Particle sorting along the view direction is required for proper blending and casting shadows from particles requires non-standard shadow algorithms. A recent technology that could be used to adress these technical challenges is hardware accelerated ray tracing. However there is a lack of performance data gathered from this type of hardware. Objectives. The objective of this thesis is to measure the performance of a prototype that uses hardware accelerated ray tracing to render particles that cast shadows. Methods. A prototype is created and measurements of the ray tracing time are made. The scene used for the benchmark test is a densely packed particle volume of highly transparent particles, resulting in a scene that looks similar to smoke. Particles are sorted along a ray by repeatedly tracing rays against the scene and incrementing the ray origin past the previous intersection point until it has passed all the objects that lie along the ray. Results. Only a small number of particles can be rendered if real time rendering speeds are desired. High quality shadows can be produced in a way that is very simple compared to texture based methods. Conclusions. Future hardware speed ups can improve the rendering speeds but more sophisticated sorting methods are needed to render larger amounts of particles.