Filters

2006 - 20073
Reset filters

Settings

Author: Ritschel, Tobias × Start date: 2006 × End date: 2009 × Has files: true ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Interactive Illumination with Coherent Shadow Maps
    (The Eurographics Association, 2007) Ritschel, Tobias; Grosch, Thorsten; Kautz, Jan; Mueller, Stefan; Jan Kautz and Sumanta Pattanaik
    We present a new method for interactive illumination computations based on precomputed visibility using coherent shadow maps (CSMs). It is well-known that visibility queries dominate the cost of physically based rendering. Precomputing all visibility events, for instance in the form of many shadow maps, enables fast queries and allows for real-time computation of illumination but requires prohibitive amounts of storage. We propose a lossless compression scheme for visibility information based on shadow maps that efficiently exploits coherence. We demonstrate a Monte Carlo renderer for direct lighting using CSMs that runs entirely on graphics hardware. We support spatially varying BRDFs, normal maps, and environment maps all with high frequencies, spatial as well as angular. Multiple dynamic rigid objects can be combined in a scene. As opposed to precomputed radiance transfer techniques, that assume distant lighting, our method includes distant lighting as well as local area lights of arbitrary shape, varying intensity, or anisotropic light distribution that can freely vary over time.
  • Thumbnail Image
    Item
    Multiresolution GPU Mesh Painting
    (The Eurographics Association, 2006) Ritschel, Tobias; Botsch, Mario; Müller, Stefan; Dieter Fellner and Charles Hansen
    Mesh painting is a well accepted and very intuitive metaphor for adding high-resolution detail to a given 3D model: Using a brush interface, the designer simply paints fine-scale texture or geometry information onto the surface. In this paper we propose a fully GPU-accelerated mesh painting technique, which provides real-time feedback even for highly complex meshes. Our method can handle arbitrary input meshes, which are considered as base meshes for Catmull-Clark subdivision. Representing the surface by an atlas of geometry images and exploiting programmable vertex and fragment shaders allows for highly efficient LoD rendering and surface manipulation. Our painting metaphor supports real-time texturing, sculpting, smoothing, and multiresolution surface deformations.
  • Thumbnail Image
    Item
    Fast GPU-based Visibility Computation for Natural Illumination of Volume Data Sets
    (The Eurographics Association, 2007) Ritschel, Tobias; Paolo Cignoni and Jiri Sochor
    Pre-computed radiance transfer (PRT) has been used to render volumetric data under distant low-frequency illumination at real-time rates, including natural illumination, soft shadows, attenuation from semi-transparent occluders and multiple scattering. PRT requires a lengthy pre-process, which is acceptable only for static volume data. However, in practical volume rendering, general transfer functions are used. Manipulating such a transfer function will result in a dynamic radiance transfer which has to be re-computed. This work proposes a fast way for this re-computation. While previous work has used CPU Monte Carlo ray-tracing for pre-computation and requires time in the order of many minutes, our GPU implementation uses a hierarchical visibility approximation implemented entirely on the GPU and requires only a few seconds for typical scenes.