CSG Ray Tracing Revisited: Interactive Rendering of Massive Models Made of Non-planar Higher Order Primitives
GRAPP 2017. Proceedings
International Conference on Computer Graphics Theory and Applications (GRAPP) <12, 2017, Porto, Portugal>
In many scientific and engineering areas, CAD models are constructed by combining simple primitives using Boolean set operations. Rendering such a dataset usually requires a preprocess, where the surface of the CAD model is approximated by an often highly complex triangle mesh. Real-time ray tracing provides an alternative to triangle rasterization as it allows for the direct visualization of (higher-order) solid and planar primitives without having to triangulate them. Additionally, Boolean compositing operations can be performed implicitly per ray, primitives have low storage requirements, and curved surfaces appear pixel-accurate. In this paper we demonstrate these properties using massive real-world CAD models.
Real-Time Parallel Streamsurface Computation
München, TU, Master Thesis, 2016
Streamsurfaces are one of the powerful visualization tools, which are used to gain insight into characteristics and features of flow fields. In practice, streamsurfaces are approximated by triangulating adjacent pairs of integral curves, originating from a seeding line. The generation of integral curves bears quite some similarities to ray tracing algorithms used in physically based renderers. Although, the techniques used in ray tracing may not have good performance in the streamline computation context due to their different computational nature, they can be optimized for streamline computation by introducing some modifications. In this master thesis, I present my work on accurate streamsurface computation and rendering in real-time, by exploiting the scalability and portability features of parallel architectures in heterogeneous computing, and utilizing concepts from physically based rendering. To improve the efficiency, I use a scheduler to divide the streamsurface computation and rendering tasks on different devices proportional to their computation powers. Additionally, I apply acceleration structures and the concepts of caching to improve the efficiency and utilization of streamsurface generation on modern GPUs and CPUs to achieve real-time results. Furthermore, the possible impact of applying ray-packing and ray-sorting to the streamline computation is investigated.
The IQmulus Urban Showcase: Automatic Tree Classification and Identification in Huge Mobile Mapping Point Clouds
ISPRS Congress Prague 2016
International Society for Photogrammetry and Remote Sensing Congress (ISPRS) <23, 2016, Prague, Czech Republic>
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLI-B3
Current 3D data capturing as implemented on for example airborne or mobile laser scanning systems is able to efficiently sample the surface of a city by billions of unselective points during one working day. What is still difficult is to extract and visualize meaningful information hidden in these point clouds with the same efficiency. This is where the FP7 IQmulus project enters the scene. IQmulus is an interactive facility for processing and visualizing big spatial data. In this study the potential of IQmulus is demonstrated on a laser mobile mapping point cloud of 1 billion points sampling ~ 10 km of street environment in Toulouse, France. After the data is uploaded to the IQmulus Hadoop Distributed File System, a workflow is defined by the user consisting of retiling the data followed by a PCA driven local dimensionality analysis, which runs efficiently on the IQmulus cloud facility using a Spark implementation. Points scattering in 3 directions are clustered in the tree class, and are separated next into individual trees. Five hours of processing at the 12 node computing cluster results in the automatic identification of 4000+ urban trees. Visualization of the results in the IQmulus fat client helps users to appreciate the results, and developers to identify remaining flaws in the processing workflow.
Visualization of Marine Sand Dune Displacements Utilizing Modern GPU Techniques
ISPRS Geospatial Week 2015
ISPRS Geospatial Week <2015, La Grande Motte, France>
Quantifying and visualizing deformation and material fluxes is an indispensable tool for many geoscientific applications at different scales comprising for example global convective models (Burstedde et al., 2013), co-seismic slip (Leprince et al., 2007) or local slope deformation (Stumpf et al., 2014b). Within the European project IQmulus (http://www.iqmulus.eu) a special focus is laid on the efficient detection and visualization of submarine sand dune displacements. In this paper we present our approaches on the visualization of the calculated displacements utilizing modern GPU techniques to enable the user to interactively analyze intermediate and final results within the whole workflow.
Enabling Virtual Assembly Training in and beyond the Automotive Industry
Proceedings of the VSMM 2012
International Conference on Virtual Systems and MultiMedia (VSMM) <18, 2012, Milan, Italy>
Virtual assembly training systems show a high potential to complement or even replace physical setups for training of assembly processes in and beyond the automotive industry. The precondition for the breakthrough of virtual training is that it overcomes the problems of former approaches. The paper presents the design approach taken during the development of a game-based, virtual training system for procedural assembly knowledge in the EU-FP7 project VISTRA. One key challenge to address when developing virtual assembly training is the extensive authoring effort for setting up virtual environments. Although knowledge from the product and manufacturing design is available and could be used for virtual training, a concept for integration of this data is still missing. This paper presents the design of a platform which transfers available enterprise data into a unified model for virtual training and thus enables virtual training of workers at the assembly line before the physical prototypes exist. The data requirements and constraints stemming from industrial partners involved in the project will be discussed. A second hurdle for virtual training is the insufficient user integration and acceptance. In this context, the paper introduces an innovative hardware set-up for game-based user interaction, which has been chosen to enhance user involvement and acceptance of virtual training