Stefan Hiller

Floating Points : A Method for Computing Stipple Drawings

We present a method for computer generated pen‐and‐ink illustrations by the simulation of stippling. In a stipple drawing, dots are used to represent tone and also material of surfaces. We create such drawings by generating an initial dot set which is then processed by a relaxation method based on Voronoi diagrams. The point patterns generated are approximations of Poisson disc distributions and can also be used for integrating functions or the positioning of objects. We provide an editor similar to paint systems for interactively creating stipple drawings. This makes it possible to create such drawings within a matter of hours, instead of days or even weeks when the drawing is done manually.

Beyond stippling - Methods for Distributing Objects on the Plane

Conventionally, stippling is an effective technique for representing surfaces in pen‐and‐ink. We present new efficientmethods for stipple drawings by computer. In contrast to already existing techniques, arbitrary shapes canbe used in place of dots. An extension of Lloyds Method enables us to position small objects on a plane in a visuallypleasing form. This allows us to generate new illustration styles. Similar methods can be used for positioningobjects in other applications.

A graphics hardware accelerated algorithm for nearest neighbor search

We present a GPU algorithm for the nearest neighbor search, an important database problem. The search is completely performed using the GPU: No further post-processing using the CPU is needed. Our experimental results, using large synthetic and real-world data sets, showed that our GPU algorithm is several times faster than its CPU version.

Hardware Rendering of 3D Geometry with Elevation Maps

We present a generic framework for realtime rendering of 3D surfaces. We use the common elevation map primitive, by which a given surface is decomposed into a set of patches. Each patch is parameterized as an elevation map over a planar domain and resampled on a regular grid. While current hardware accelerated rendering approaches require conversion of this representation back into a triangle mesh or point set, we propose to render the elevation maps directly in a hardware accelerated environment. We use one base data set to render each patch in the common vertex and fragment shader pipeline. We implement mesh- or point-based rendering by using a base mesh or a base point set respectively. This provides the basis for the underlying primitive for the final rendering. We show the benefits of this method for splat rendering by replacing attribute blending through a simplified and fast attribute interpolation. This results in rendering acceleration as well as an improvement in visual quality when compared to previous approaches