Voxel-based global illumination

Abstract

Figure 1: Using voxel-based visibility (center), we are able to display real-time near-field illumination with directional occlusion (left, 25 fps) and interactive global illumination (right, 4.9 fps). The indirect light is exaggerated for visualization. AbstractComputing a global illumination solution in real-time is still an open problem. We introduce Voxel-based Global Illumination (VGI), a scalable technique that ranges from real-time near-field illumination to interactive global illumination solutions. To obtain a voxelized scene representation, we introduce a new atlas-based boundary voxelization algorithm and an extension to a fast rayvoxel intersection test. Similar to screen-space illumination methods, VGI is independent of the scene complexity. Using voxels for indirect visibility enables real-time near-field illumination without the screen-space artifacts of alternative methods. Furthermore, VGI can be extended to interactive, multi-bounce global illumination solutions like path tracing and instant radiosity.

Fast light-map computation with virtual polygon lights

“…Voxel-based global illumination techniques (e.g. [Thiedemann et al 2011] or [Crassin et al 2011]) can perform an approximate light transport even for dynamic objects interactively. Since voxels are normally not aligned to the geometry, they may lead to objectionable artifacts such as light leaks or re-rasterization problems and are therefore very problematic for high-quality lightmap generation.…”

Real-time diffuse global illumination using radiance hints

“…The method also suffers from popping artifacts due to view-dependent occlusion information. Thiedemann et al [2011] introduced an interactive volume-based global illumination method, where the spatial occupancy and color data are generated by injecting a geometry texture atlas containing point samples of the polygonal geometry. The authors propose an optimized ray marching scheme for intersecting the gathering rays with the volume data.…”

“…Ambient occlusion [Zhukov et al 1998] has been extensively used as a statistical measure of light attenuation according to the closeness of geometry in the vicinity of p, but unfortunately, it leads to erroneous shadowing of areas with strong indirect light exchange (corners, opposite surfaces etc). In volume-based approaches, blocking voxels are injected in the volume representation of the scene either by full-scene voxelization [Gaitatzes et al 2010;Thiedemann et al 2011;Mavridis and Papaioannou 2011] or by injecting view-dependent blocking voxels from the RSM and camera depth information [Kaplanyan and Dachsbacher 2010]. With Antiradiance [Dachsbacher et al 2007], light that should be reflected by blocking geometry is negatively transmitted through surface boundaries and canceled out by unobstructed light at the next surface.…”

“…To this end, Table 1 summarizes some key capabilities and requirements of the proposed method (RH), two geometry injection volume-based methods (VBGI1 and VBGI2), RSM sampling/splatting (RSM) and Light Propagation Volumes (LPV). VBGI1 corresponds to the texture atlas point injection technique by Thiedemann et al [2011], while VBGI2 is the tesselation-based point injection method described in [Mavridis and Papaioannou 2011]. Please refer to the Related Work section for a brief overview of the above techniques.…”

Radiance Caching with Environment Maps

“…Using voxel cone tracing, Crassin et al [7] was able to achieve interactive indirect illumination as an approximation. VGI [30], a similar approach, uses path tracing with voxels to achieve performance improvements.…”