Christian Eisenacher

Walt Disney (United States)

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Marc Stamminger

Friedrich-Alexander-Universität Erlangen-Nürnberg

Charles Loop

Nvidia (United Kingdom)

Sylvain Lefèbvre

Université de Lorraine

Gregory Nichols

Latitude Pharmaceuticals (United States)

Quirin Meyer

Coburg University of Applied Sciences

Brent Burley

Walt Disney (United States)

Matthäus G. Chajdas

Akademie Mode & Design

Pau Panareda Busto

University of Bonn

Peter Hastreiter

Universitätsklinikum Erlangen

Frank Enders

Sorbonne Université

Cooperative Institutions

Walt Disney (United States)

Friedrich-Alexander-Universität Erlangen-Nürnberg

Institut national de recherche en informatique et en automatique

University of Stuttgart

Stanford University

Adobe Systems (United States)

Nvidia (United Kingdom)

Universitätsklinikum Erlangen

Centre Inria de l'Université de Lorraine

Institut Supérieur d'Électronique de Paris

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GPU accelerated normalized mutual information and B-spline transformation

Visual Computing for Biomedicine (2008)

Matthias Teßmann Christian Eisenacher Frank Enders Marc Stamminger Peter Hastreiter

Visualization of multimodal images in medicine and other application areas requires correct and efficient registration. Optimally, the alignment operation is made an integral part of the rendering process. Voxel based approaches using mutual information ensure high quality similarity measurement. As a limiting factor, high computational load is caused since for every iteration of the optimization procedure one volume is transformed into the coordinate system of the other, a 2D histogram is generated and mutual information is computed. The expensive trilinear interpolation operations are well supported by 3D texture mapping hardware. However, existing strategies compute the histogram and mutual information on the CPU and thus require a cost intensive data transfer. Overcoming this considerable bottleneck, we introduce a new approach that efficiently supports all computations on modern graphics cards. This makes expensive data transfers from GPU to main memory dispensable. Due to its modularity, the presented approach can be integrated into general frameworks. As a major result, the speed improvement over existing GPU-CPU strategies amounts to a factor of 4 and over pure conventional CPU techniques to more than a factor of 10. Overall, the suggested strategy contributes considerably to integration of multimodal registration directly into interactive volume visualization.

Texture memory

Interpolation

10.2312/vcbm/vcbm08/117-124

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Citations (13)

Sorted Deferred Shading for Production Path Tracing

Computer Graphics Forum (2013)

Christian Eisenacher Gregory Nichols Andrew Selle Brent Burley

Abstract Ray‐traced global illumination (GI) is becoming widespread in production rendering but incoherent secondary ray traversal limits practical rendering to scenes that fit in memory. Incoherent shading also leads to intractable performance with production‐scale textures forcing renderers to resort to caching of irradiance, radiosity, and other values to amortize expensive shading. Unfortunately, such caching strategies complicate artist workflow, are difficult to parallelize effectively, and contend for precious memory. Worse, these caches involve approximations that compromise quality. In this paper, we introduce a novel path‐tracing framework that avoids these tradeoffs. We sort large, potentially out‐of‐core ray batches to ensure coherence of ray traversal. We then defer shading of ray hits until we have sorted them, achieving perfectly coherent shading and avoiding the need for shading caches.

Shading

Shader

Path tracing

Global illumination

Parallel rendering

10.1111/cgf.12158

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Citations (50)

Virtual Texture Mapping 101

A K Peters/CRC Press eBooks (2018)

Matthäus G. Chajdas Christian Eisenacher Marc Stamminger Sylvain Lefèbvre

In this chapter, the authors describe a basic virtual texture mapping (VTM) system. It is simple and fast, even on older hardware. The authors explore a certain pointers on how to further improve performance, should reader's application or game require it. Even with newer hardware that might natively support page faults, strategies for loading, compressing and filtering textures will still be required. The authors investigate various implementation issues with a strong emphasis on texture filtering. While early texture management schemes were designed for a single large texture, VTM systems are more flexible and mimic the virtual memory management of the OS: textures are divided into small tiles, or pages. The page handler loads requested tiles from disk, uploads them onto the Graphics processing unit, and updates the indirection texture. A simple approach is to render the complete scene with a special shader that translates the virtual texture coordinates into a tile ID.

Texture memory

Texture (cosmology)

Texture atlas

Projective texture mapping

10.1201/9781351261524-4

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Citations (4)

Handling scene constraints for pose-based caching

Gene S. Lee Christian Eisenacher Andy Lin Noel Villegas

This paper presents a conservative, uniform method for handling scene constraints, such as look at and parent, in a pose-based caching system. The constraints are organized into a dependency graph where nodes represent the control caches of a rig, and directed arcs link the rigs to specific control caches. For any animation update, the dependency graph indicates which cache to clear and which other rigs to subsequently update. This method supports pre-evaluation, avoids expensive state tracking, and is easy to implement. The result is a seamless experience that works with all types of constraints while preserving real-time performance.

Dependency graph

10.1145/3084363.3085047

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Citations (0)

Virtual Texture Mapping 101

A K Peters/CRC Press eBooks (2010)

Matthäus G. Chajdas Christian Eisenacher Marc Stamminger Sylvain Lefèbvre

From the literature, we may extract two diﬀerent approaches: object-space and image-space algorithms. However, most modern algorithms work in either image space or hybrid space. For the purposes of this chapter, we are interested in GPU-based algorithms, and these are the ones we will present. Werefer the interested reader to the works of [Isenberg et al. 03] and [Hartner et al. 03] for overviews and deep comparisons on CPU-based silhouette extraction algorithms.

Texture (cosmology)

Projective texture mapping

10.1201/b10648-14

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Citations (3)

Level-of-Detail for Production-Scale Path Tracing

Vision Modeling and Visualization (2015)

Magdalena Prus Christian Eisenacher Marc Stamminger

Tracing

Path tracing

10.2312/vmv.20151260

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Citations (1)

Real-time view-dependent rendering of parametric surfaces

Christian Eisenacher Quirin Meyer Charles Loop

We propose a view-dependent adaptive subdivision algorithm for rendering parametric surfaces on parallel hardware. Our framework allows us to bound the screen space error of a piecewise linear approximation. We naturally assign more primitives to curved areas while keeping quads large for flatter parts of the model and avoid cracks resulting from the polygonal approximation of non-uniform patch subdivision. The overall algorithm is simple, fits current GPUs extremely well, and is surprisingly fast while producing little to no artifacts.

Subdivision surface

Tiled rendering

Real-time rendering

3D rendering

Alternate frame rendering

10.1145/1507149.1507172

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Citations (28)

Instant Texture Synthesis by Numbers

Pau Panareda Busto Christian Eisenacher Sylvain Lefèbvre Marc Stamminger

Appearance Space Texture Synthesis (ASTS) provides fast texture synthesis by example. Unfortunately, speed is only achieved at the cost of a long pre-processing step. This is tedious for artists and limits the input resolution. In addition, the aggressively pruned search space results in strong artifacts when synthesizing multiple textures under user guidance (Texture-By-Numbers, TBN). In this thesis, we replace the k-coherence search step used by most modern synthesis algorithms with a new parallel, coherent random walk. We show that this drastically improves the synthesis quality with TBN, while maintaining the parallel nature, speed, and flexibility of the original ASTS runtime. Since it removes the expensive pre-computation of k-coherent candidates, we are able to use larger inputs, and start synthesis much faster. This is essential for artists designing high-quality exemplars.

Texture Synthesis

Texture (cosmology)

View synthesis

10.2312/pe/vmv/vmv10/081-085

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Citations (16)

Texture Synthesis From Photographs

Computer Graphics Forum (2008)

Christian Eisenacher Sylvain Lefebvre Marc Stamminger

Abstract The goal of texture synthesis is to generate an arbitrarily large high‐quality texture from a small input sample. Generally, it is assumed that the input image is given as a flat, square piece of texture, thus it has to be carefully prepared from a picture taken under ideal conditions. Instead we would like to extract the input texture from any surface from within an arbitrary photograph. This introduces several challenges: Only parts of the photograph are covered with the texture of interest, perspective and scene geometry introduce distortions, and the texture is non‐uniformly sampled during the capture process. This breaks many of the assumptions used for synthesis. In this paper we combine a simple novel user interface with a generic per‐pixel synthesis algorithm to achieve high‐quality synthesis from a photograph. Our interface lets the user locally describe the geometry supporting the textures by combining rational Bézier patches. These are particularly well suited to describe curved surfaces under projection. Further, we extend per‐pixel synthesis to account for arbitrary texture sparsity and distortion, both in the input image and in the synthesis output. Applications range from synthesizing textures directly from photographs to high‐quality texture completion.

Texture Synthesis

Texture atlas

Projective texture mapping

Texture filtering

Bidirectional texture function

Texture (cosmology)

Texture compression

Displacement mapping

Distortion (music)

Perspective distortion

10.1111/j.1467-8659.2008.01139.x

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Citations (22)

Real-time Patch-Based Sort-Middle Rendering on Massively Parallel Hardware

Charles Loop Christian Eisenacher

Recently, sort-middle triangle rasterization, implemented as software on a manycore GPU with vector units (Larabee), has been proposed as an alternative to hardware rasterization. The main reasoning is, that only a fraction of the time per frame is spent sorting and rasterizing triangles. However is this still a valid argument in the context of geometry amplification when the number of primitives increases quickly? A REYES like approach, sorting parametric patches instead, could avoid many of the problems with tiny triangles. To demonstrate that software rasterization with geometry amplification can work in real-time, we implement a tile based sort-middle rasterizer in CUDA and analyze its behavior: First we adaptively subdivide rational bicubic B´ezier patches. Then we sort those into buckets, and for each bucket we dice, grid-shade, and rasterize the micropolygons into the corresponding tile using on-chip caches. Despite being limited by the amount of available shared memory, the number of registers and the lack of an L3 cache, we manage to rasterize 1600×1200 images, containing 200k sub-patches, at 10-12 fps on an nVidia GTX 280. This is about 3x to 5x slower than a hybrid approach subdividing with CUDA and using the HW rasterizer. We hide cracks caused by adaptive subdivision using a flatness metric in combination with rasterizing B´ezier convex hulls. Using a k-buffer with a fuzzy z-test we can render transparent objects despite the overlap our approach creates. Further, we introduce the notion of true back patch culling, allowing us to simplify crack hiding and sampling.

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Citations (7)