Volumetric Ambient Occlusion
نویسندگان
چکیده
This paper presents a new GPU-based algorithm to compute ambient occlusion. We first examine how ambient occlusion is related to the physically founded rendering equation. The correspondence is made by introducing a fuzzy membership function that defines what “near occlusions” mean. Then we develop a method to calculate ambient occlusion in real-time without any pre-computation. The proposed algorithm is based on a novel interpretation of ambient occlusion that measures how big portion of the tangent sphere of the surface belongs to the set of occluded points. The integrand of the new formula has low variation, thus can be estimated accurately with a few samples. Thus, the algorithm can effectively be used in real-time systems and games to cheaply approximate global illumination effects.
منابع مشابه
A Comparison of Volumetric Illumination Methods by Considering their Underlying Mathematical Models
In this paper, we study and analyze seven state-of-the-art volumetric illumination methods, in order to determine their differences with respect to the underlying theoretical mathematical models and numerical problems potentially arising during implementation. The chosen models are half angle slicing, directional occlusion shading, multidirectional occlusion shading, shadow volume propagation, ...
متن کاملInteractive Volume Rendering with Dynamic Ambient Occlusion and Color Bleeding
We propose a method for rendering volumetric data sets at interactive frame rates while supporting dynamic ambient occlusion as well as an approximation to color bleeding. In contrast to ambient occlusion approaches for polygonal data, techniques for volumetric data sets have to face additional challenges, since by changing rendering parameters, such as the transfer function or the thresholding...
متن کاملFast Occlusion Sweeping
While realistic illumination significantly improves the visual quality and perception of rendered images, it is often very expensive to compute. In this paper, we propose a new algorithm for embedding a global ambient occlusion computation within the fast sweeping algorithm while determining isosurfaces. With this method we can approximate ambient occlusion for rendering volumetric data with mi...
متن کاملA Directional Occlusion Shading Model for Interactive Direct Volume Rendering
Volumetric rendering is widely used to examine 3D scalar fields from scanners and direct numerical simulation datasets. One key aspect of volumetric rendering is the ability to provide shading cues to aid in understanding structure contained in the datasets. While shading models that reproduce natural lighting conditions have been shown to better convey depth information and spatial relationshi...
متن کاملIsosurface Ambient Occlusion and Soft Shadows with Filterable Occlusion Maps
Volumetric data sets are often examined by displaying isosurfaces, surfaces where the data or function takes on a given value. We propose a new method for rendering isosurfaces at interactive rates while supporting dynamic ambient occlusion and/or soft shadows and requiring minimal pre-computation time. By approximating the occlusion in a region as the percentage of occluding voxels in that reg...
متن کامل