Computing ambient occlusion in screen-space (SSAO) is a common technique in real-time rendering applications which use rasterization to process 3D triangle data. However, one of the most critical problems emerging in screenspace is the lack of information regarding occluded geometry which does not pass the depth test and is therefore not resident in the G-buffer. These occluded fragments may have an impact on the proximity-based shadowing outcome of the ambient occlusion pass. This not only decreases image quality but also prevents the application of SSAO on multiple layers of transparent surfaces where the shadow contribution depends on opacity.We propose a novel approach to the SSAO concept by taking advantage of per-pixel fragment lists to store multiple geometric layers of the scene in the G-buffer, thus allowing order independent transparency (OIT) in combination with high quality, opacity-based ambient occlusion (OITAO). This Abuffer concept is also used to enhance overall ambient occlusion quality by providing stable results for low-frequency details in dynamic scenes. Furthermore, a flexible compression-based optimization strategy is introduced to improve performance while maintaining high quality results.

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We introduce deferred warping, a novel approach for real-time deformation of 3D objects attached to an animated or manipulated surface. Our target application is virtual prototyping of garments where 2D pattern modeling is combined with 3D garment simulation which allows an immediate validation of the design. The technique works in two steps: First, the surface deformation of the target object is determined and the resulting transformation field is stored as a matrix texture. Then the matrix texture is used as look-up table to transform a given geometry onto a deformed surface. Splitting the process in two steps yields a large flexibility since different attachment types can be realized by simply defining specific mapping functions. Our technique can directly handle complex topology changes within the surface. We demonstrate a fast implementation in the vertex shading stage allowing the use of highly decorated surfaces with millions of triangles in real-time.

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Scene graphs are widely used as a description of spatial relations between objects in a scene. Current scene graphs use linear transformations for this purpose. This limits the relation of two objects in the hierarchy to simple transformations like sheer, translation, rotation and scaling. In contrast to this, we want to represent and control deformations that result from propagating the dynamics of objects to deformable attached objects. Our solution is to replace the linear 4x4 matrix-based transformation of a scene graph by a more generic trilinear transformation. The linear transformation allows the composition of the transformation hierarchy into one transformation. Our approach additionally allows the handling of deformations on the same level. Building on this concept we present a system capable of real-time rendering. The computations of the applied deformations of the scene graph are performed in real-time on the GPU. We allow the approximation of arbitrary nonlinear transformations and deformations by utilising grids of trilinear transformations in our system. As an application we show geometric attachments on deformable objects and their deformation on a scene graph level.