André Stork

Spacedesign: a mixed reality workspace for aesthetic industrial design

Spacedesign is an innovative mixed reality (MR) application addressed to aesthetic design of free form curves and surfaces. It is a unique and comprehensive approach which uses task-specific configurations to support the design workflow from concept to mock-up evaluation and review. The first-phase conceptual design benefits from a workbench-like 3-D display for free hand sketching, surfacing and engineering visualization. Semitransparent stereo glasses augment the pre-production physical prototype by additional shapes, textures and annotations. Both workspaces share a common interface and allow collaboration and cooperation between different experts, who can configure the system for the specific task. A faster design workflow and CAD data consistency can be thus naturally achieved. Tests and collaborations with designers, mainly from automotive industry, are providing systematic feedback for this ongoing research. As far as the authors are concerned, there is no known similar approach that integrates the creation and editing phase of 3D curves and surfaces in virtual and augmented reality (VR/AR). Herein we see the major contribution of our new application.

A multi-layered architecture for sketch-based interaction within virtual environments

Abstract In this article, we describe a multi-layered architecture for sketch-based interaction within virtual environments. Our architecture consists of eight hierarchically arranged layers that are described by giving examples of how they are implemented and how they interact. Focusing on table-like projection systems (such as Virtual Tables or Responsive Workbenches) as human-centered output-devices, we show examples of how to integrate parts or all of the architecture into existing domain-specific applications — rather than realizing new general sketch applications — to make sketching an integral part of the next-generation human–computer interface.

Efficient GPU Data Structures and Methods to Solve Sparse Linear Systems in Dynamics Applications

We present graphics processing unit (GPU) data structures and algorithms to efficiently solve sparse linear systems that are typically required in simulations of multi‐body systems and deformable bodies. Thereby, we introduce an efficient sparse matrix data structure that can handle arbitrary sparsity patterns and outperforms current state‐of‐the‐art implementations for sparse matrix vector multiplication. Moreover, an efficient method to construct global matrices on the GPU is presented where hundreds of thousands of individual element contributions are assembled in a few milliseconds. A finite‐element‐based method for the simulation of deformable solids as well as an impulse‐based method for rigid bodies are introduced in order to demonstrate the advantages of the novel data structures and algorithms. These applications share the characteristic that a major computational effort consists of building and solving systems of linear equations in every time step. Our solving method results in a speed‐up factor of up to 13 in comparison to other GPU methods.

Fast delivery of 3D web content: a case study

Despite many advances in mesh compression methods within the past two decades, there is still no consensus about a standardized compact mesh encoding format for 3D Web applications. In order to facilitate the design of a future platform-independent solution, this paper investigates the crucial trade-off between compactness of the compressed representation and decompression time. Our case study evaluates different encoding formats, combined with various transmission bandwidths, using different client devices. Results indicate that good compression rates, and at the same time a fast decompression, can be achieved by exploiting existing browser features and by minimizing the complexity of operations that have to be performed inside the JavaScript layer. Our findings are summarized in concrete recommendations for future standards.

Constraint stroke-based oversketching for 3D curves

In this paper we present an extended approach for stroke oversketching. The stroke oversketching technique changes a curve by redrawing parts of it. Finding the part to replace and smoothing the transition is done automatically. Our extension to oversketching constraints the change of the curve to one single side profile leaving the other side profiles of the curve unchanged. Additionally we present the advantage of using this approach in car design following the classic four-side-view drawing approach.

Enabling virtual assembly training in and beyond the automotive industry

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.

Efficient and precise solid modelling using a 3D input device

To ailnultaneously model 3D objects efficiently and precisely seems somewhat contradictory. Several approaches have been clcvclopcd to do tither inaccurate but fast 3D sketching using 2D or 3D input devices or to model precisely with conventional 2D techniques, We believe that the reason why 3D input devices have not been successful outside of imprecise sketching is due to a lack of appropriate rntcraction techniques that drive 3D devices to their lull potential.

The daylight blocking optical stereo see-through HMD

In this paper we present an innovative daylight blocking optical stereo see-through HMD. Its outstanding capability is to pixelwise block incident daylight before super-imposing virtual content on the real scene. By doing so the device allows to seamlessly mix real and virtual content without the well-known effects of other optical see-through displays where real content will always shine through virtual content. To our knowledge related work on daylight blocking displays is very limited and we present the first commercial HMD available.

Knowledge sharing by information retrieval in the semantic web

Effective and efficient information retrieval, knowledge sharing and combining has become an essential part of more and more professional tasks and work flows in different kinds of projects. Our aim is to investigate the use of emerging Semantic Web technologies, tools, and standards in the support of effective information retrieval in real multi-disciplinary activities, such as innovative product design. This paper presents an approach to knowledge sharing and information support that has been developed and adopted, the information system architecture that is being developed to test both this approach, and the Semantic Web techniques that are used in its implementation, some early results, and a discussion of related work in information systems and Semantic Web techniques and tools.

Interactive Semantic Enrichment of 3D Cultural Heritage Collections

Virtual Surrogates of Cultural Heritage (CH) objects are seriously being considered in professional activities such as conservation and preservation, exhibition planning, packing, and scholarly research, among many other activities. Although this is a very positive development, a bare 3D digital representation is insufficient and poor for fulfilling the full range of professional activities. In this paper, we present the first interactive semantic enrichment tool for 3D CH collections that is fully based on the CIDOC-CRM schema and that fully supports its sophisticated annotation model. The tool eases the user interaction, allowing inexperienced users without previous knowledge on semantic models or 3D modeling to employ it and to conceive it for the professional workflow on 3D annotations. We illustrate the capabilities of our tool in the context of the Saalburg fort, during Roman times (2nd century AD), for the protection of the Limes on the Taunus hills in Germany.