Screen space ambient occlusion for virtual and mixed reality factory planning

Abstract

Ambient occlusion represents one aspect of global illumination, simulating the actual accessibility of surfaces for indirect illumination due to occlusion of nearby geometry. Recently the approximation in screen space made it feasible for realtime applications. We focus on the utilization of screen space ambient occlusion (SSAO) in virtual and mixed reality environments, especially considering scenes with a large spatial extent and massive amounts of data, typical for industrial factory planning scenarios. Therefore, a sophisticated screen space approach closer to the original definition of ambient occlusion is presented and compared with existing techniques considering the visual quality. Furthermore, we introduce a method to avoid the disappearance of the SSAO effect in depth for scenes with a large spatial extent. A user study compares the impact of our approach to standard SSAO and standard phong shading, regarding the several cues of human depth perception in a virtual and a mixed reality scenario. The evaluation underlines the benefit of our approach for pure virtual scenes and additionally illustrates a different perception of the cues regarding virtual scenes with a half transparent overlayimage of the real world, typical for mixed reality discrepancy check scenarios.