Browsing by Author "Rist, Florian"

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    Invertible Paradoxic Loop Structures for Transformable Design
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Li, Zijia; Nawratil, Georg; Rist, Florian; Hensel, Michael; Panozzo, Daniele and Assarsson, Ulf
    We present an interactive tool compatible with existing software (Rhino/Grasshopper) to design ring structures with a paradoxic mobility, which are self-collision-free over the complete motion cycle. Our computational approach allows non-expert users to create these invertible paradoxic loops with six rotational joints by providing several interactions that facilitate design exploration. In a first step, a rational cubic motion is shaped either by means of a four pose interpolation procedure or a motion evolution algorithm. By using the representation of spatial displacements in terms of dual-quaternions, the associated motion polynomial of the resulting motion can be factored in several ways, each corresponding to a composition of three rotations. By combining two suitable factorizations, an arrangement of six rotary axes is achieved, which possesses a 1-parametric mobility. In the next step, these axes are connected by links in a way that the resulting linkage is collision-free over the complete motion cycle. Based on an algorithmic solution for this problem, collision-free design spaces of the individual links are generated in a post-processing step. The functionality of the developed design tool is demonstrated in the context of an architectural and artistic application studied in a master-level studio course. Two results of the performed design experiments were fabricated by the use of computer-controlled machines to achieve the necessary accuracy ensuring the mobility of the models.
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    Precomputed Radiative Heat Transport for Efficient Thermal Simulation
    (The Eurographics Association and John Wiley & Sons Ltd., 2023) Freude, Christian; Hahn, David; Rist, Florian; Lipp, Lukas; Wimmer, Michael; Chaine, Raphaƫlle; Deng, Zhigang; Kim, Min H.
    Architectural design and urban planning are complex design tasks. Predicting the thermal impact of design choices at interactive rates enhances the ability of designers to improve energy efficiency and avoid problematic heat islands while maintaining design quality. We show how to use and adapt methods from computer graphics to efficiently simulate heat transfer via thermal radiation, thereby improving user guidance in the early design phase of large-scale construction projects and helping to increase energy efficiency and outdoor comfort. Our method combines a hardware-accelerated photon tracing approach with a carefully selected finite element discretization, inspired by precomputed radiance transfer. This combination allows us to precompute a radiative transport operator, which we then use to rapidly solve either steady-state or transient heat transport throughout the entire scene. Our formulation integrates time-dependent solar irradiation data without requiring changes in the transport operator, allowing us to quickly analyze many different scenarios such as common weather patterns, monthly or yearly averages, or transient simulations spanning multiple days or weeks. We show how our approach can be used for interactive design workflows such as city planning via fast feedback in the early design phase.
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    Sit & Relax: Interactive Design of Body-Supporting Surfaces
    (The Eurographics Association and John Wiley & Sons Ltd., 2018) Leimer, Kurt; Birsak, Michael; Rist, Florian; Musialski, Przemyslaw; Fu, Hongbo and Ghosh, Abhijeet and Kopf, Johannes
    We propose a novel method for interactive design of well-fitting body-supporting surfaces that is driven by the pressure distribution on the body's surface. Our main contribution is an interactive modeling system that utilizes captured body poses and computes an importance field that is proportional to the pressure distribution on the body for a given pose. This distribution indicates where the body should be supported in order to easily hold a particular pose, which is one of the measures of comfortable sitting. Using our approximation, we propose the entire workflow for interactive design of C2 smooth surfaces which serve as seats, or generally, as body supporting furniture for comfortable sitting. Finally, we also provide a design tool for RHINOCEROS/GRASSHOPPER that allows for interactive creation of single designs or entire multi-person sitting scenarios. We also test the tool with design students and present several results. Our method aims at interactive design in order to help designers to create appropriate surfaces digitally without additional empirical design passes.