Ray Tracing Point Sampled Geometry

Gernot Schaufler (Massachusetts Institute of Technology)
Henrik Wann Jensen (Stanford University)

Two bunnies each represented using approximately 35.000 points. The caustic on the wood bunny due to light focused through the glass bunny has been computed using photon mapping.


We present a novel technique for ray tracing geometry represented by points. Our approach makes it possible to render high quality ray traced images with global illumination using unstructured point--sampled data thus avoiding the time-consuming process of reconstructing the underlying surface or any topological information. Compared with previous point rendering methods, our approach allows for more complex illumination models while still maintaining the simplicity of the point primitive.

Intersections with the point--sampled geometry are detected by tracing a ray through the scene until the local density of points is above a predefined threshold. We then use all the points within a fixed distance of the ray to interpolate the position, normal and any other attributes of the intersection. The considered distance from the ray must be larger than the largest ``hole'' among the points.

We demonstrate results for soft shadows, reflection and refraction, global illumination and subsurface scattering.


Gernot Schaufler and Henrik Wann Jensen: "Ray tracing point sampled geometry". Rendering Techniques 2000. Eds. Peroche and Rushmeier. Springer-Verlag, pages 319-328, 2000

pdf-file - 4.5 MB