Katja Daubert

Illuminating micro geometry based on precomputed visibility

Many researchers have been arguing that geometry, bump maps, and BRDFs present a hierarchy of detail that should be exploited for efficient rendering purposes. In practice however, this is often not possible due to inconsistencies in the illumination for these different levels of detail. For example, while bump map rendering often only considers direct illumination and no shadows, geometry-based rendering and BRDFs will mostly also respect shadowing effects, and in many cases even indirect illumination caused by scattered light. In this paper, we present an approach for overcoming these inconsistencies. We introduce an inexpensive method for consistently illuminating height fields and bump maps, as well as simulating BRDFs based on precomputed visibility information. With this information we can achieve a consistent illumination across the levels of detail. The method we propose offers significant performance benefits over existing algorithms for computing the light scattering in height fields and for computing a sampled BRDF representation using a virtual gonioreflectometer. The performance can be further improved by utilizing graphics hardware, which then also allows for interactive display. Finally, our method also approximates the changes in illumination when the height field, bump map, or BRDF is applied to a surface with a different curvature.

Efficient Cloth Modeling and Rendering

Realistic modeling and high-performance rendering of cloth and clothing is a challenging problem. Often these materials are seen at distances where individual stitches and knits can be made out and need to be accounted for. Modeling of the geometry at this level of detail fails due to sheer complexity, while simple texture mapping techniques do not produce the desired quality. In this paper, we describe an efficient and realistic approach that takes into account view-dependent effects such as small displacements causing occlusion and shadows, as well as illumination effects. The method is efficient in terms of memory consumption, and uses a combination of hardware and software rendering to achieve high performance. It is conceivable that future graphics hardware will be flexible enough for full hardware rendering of the proposed method.

Efficient light transport using precomputed visibility

We describe a method that precomputes, stores, and reuses visibility information for light transport in general parametric surfaces, triangle meshes without a global parameterization, and participating media.

Hardware‐Based Volumetric Knit‐Wear

We present a hardware‐based, volumetric approach for rendering knit wear at very interactive rates. A single stitch is represented by a volumetric texture with each voxel storing the main direction of the strands of yarn inside it. We render the knit wear in layers using an approximation of the Banks model. Our hardware implementation allows specular and diffuse material properties to change from one voxel to the next. This enables us to represent yarn made up of different components or render garments with complicated color patterns. Furthermore, our approach can handle self‐shadowing of the stitches, and can easily be adapted to also include view‐independent scattering. The resulting shader lends itself naturally to mip‐mapping, and requires no reordering of the base geometry, making it versatile and easy to use.

Advanced Environment Mapping in VR Applications

Abstract In this paper, we propose an approach for rendering diffuse and glossy reflections using environment maps. This approach is geared towards virtual reality applications, where realism and fast rendering is important. We exploit certain mathematical properties of diffuse reflections and certain features of graphics hardware for glossy reflections. This results in a very fast, single-pass rendering algorithm, which even allows to dynamically vary the incident lighting.