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Sue Sommer, Thu Helga; Kuijper, Arjan [Supervisor]; Räsch, Sascha [Advisor]

Analysis of Metrics for Image Comparison in the Context of Automated Testing of Iterative Rendering Technologies


Darmstadt, TU, Bachelor Thesis, 2021

Automatic Quality Assurance in modern software development is inevitable for cost reduction and efficiency. Besides the correctness of the software, the performance and user-perception are essential subjects of testing. For 3D visualisation software like instant3Dhub, quantifying the quality of userperception is a challenging task. We will examine different metrics with respect to their prediction of the user perception and thus the quality of the 3D visualisation. We conclude how these metrics reflect human perception and where the limits of these approaches lie.

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Räsch, Sascha; Herz, Maximilian; Behr, Johannes; Kuijper, Arjan

Efficient Compression for Server-Side G-Buffer Streaming in Web Applications


Proceedings Web3D 2017

International Conference on 3D Web Technology (WEB3D) <22, 2017, Brisbane, Australia>

Remote rendering methods enable devices with low computing power like smart phones or tablets to visualize massive data. By transmitting G-Buffers, Depth-Image-Based Rendering (DIBR) methods can be used to compensate the artefacts caused by the latency. However, the drawback is that a G-Buffer has at least twice as much data as an image. We present a method for compressing G-Buffers which provides an efficient decoding suitable for web applications. Depending on the computing power of the device, software methods, which run on the CPU, may not be fast enough for an interactive experience. Therefore, we developed a decoding which runs entirely on the GPU. As we use only standard WebGL for our implementation, our compression is suitable for every modern browser.

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Herz, Maximilian; Kuijper, Arjan [Prüfer]; Räsch, Sascha [Betreuer]

G-Buffer Compression for Remote Rendering Web Applications


Darmstadt, TU, Master Thesis, 2016

As modern CAD applications need to render big scenes it is necessary to use client-server hybrid rendering to distribute work between two machines. This can reduce the needed bandwith and enhance the rendering performance. One way to implement hybrid rendering is to render the scene into G-Buffers, send them to the client and perform deferred shading there to render the final image. With this approach there is no need to send gigabytes of 3D model data over the network. In this master thesis, we will look into different methods to compress G-Buffer data. The G-Buffer is composed of three parts (object id's, depths, normals). We will analyze to which extend common image compression algorithms like JPEG will work on these parts. There are also methods specifically for compressing normal and depth data which we will look at. We will evaluate selected algorithms to further enhance the overall G-Buffer compression ratio. A server and client application have to be developed in order to evaluate the different compression methods. To ensure that the client runs on a broad range of devices the code will be implemented as a web application using HTML5, Java Script and WebGL. Thus, only methods can be used which enable for a fast decompression even on devices with low computing capabilities. The results of this thesis will be used inside the instant3Dhub system technology, which is developed by the VCST department.

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Räsch, Sascha; Weber, Daniel [Betreuer]

Two-dimensional Circulation-preserving Fluid Simulation with Discrete Exterior Calculus


Darmstadt, TU, Bachelor Thesis, 2011

The development of efficient and stable fluid simulations is a challenging task in computer graphics. Elcott et al. [6] describe an approach, based on Discrete Exterior Calculus for simulating the fluid flow. A vorticity based formulation of the incompressible Navier-Stokes equations is used, resulting in a mass-conserving representation of the velocity field by definition. This approach preserves vorticity at a discrete level, resulting in a visually more realistic fluid flow. We extend this approach to regular grids in two dimensions. So, we avoid computationally expensive mesh constructions. We discuss non-trivial boundary conditions and arbitrary topologies. The vorticity conservation properties are compared with the classical mesh based approach of Elcott et. al. We especially analyze the corresponding pressure fields near the boundaries of inner objects.