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Dr.-Ing. Hendrik Hochstetter
address:
Universität Siegen
Lehrstuhl für Computergrafik
57076 Siegen
Recent publications:
| SCA 2017 - Evaporation and Condensation of SPH-based Fluids |
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| In this paper we present a method to simulate evaporation and condensation of liquids. Therefore, both the air and liquid phases have to be simulated. We use, as a carrier of vapor, a coarse grid for the air phase and mass-preservingly couple it to an SPH-based liquid and rigid body simulation. Since condensation only takes place on rigid surfaces, it is captured using textures that carry water to achieve high surface detail. The textures can exchange water with the air phase and are used to generate new particles due to condensation effects yielding a full two-way coupling of air phase and liquid. In order to allow gradual evaporation and condensation processes, liquid particles can take on variable sizes. Our proposed improved implicit surface definition is able to render dynamic contact angles for moving droplets yielding highly detailed fluid rendering. |
 Paper  Video The definitive Version was published in Proc. SCA' 17, https://doi.org/10.1145/3099564.3099580. |
| SIGGRAPH 2017 - Infinite Continuous Adaptivity for Incompressible SPH |
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| In this paper we introduce a novel method to adaptive incompressible SPH simulations. Instead of using a scheme with a number of fixed particle sizes or levels, our approach allows continuous particle sizes. This {enables} us to define optimal particle masses with respect to, e.g., the distance to the fluid's surface. A required change in mass due to the dynamics of the fluid is properly and stably handled by our scheme of mass redistribution. This includes temporally smooth changes in particle masses as well as sudden mass variations in regions of high flow dynamics. Our approach guarantees low spatial variations in particle size, which is a core property in order to achieve large adaptivity ratios for incompressible fluid simulations. Conceptually, our approach allows for infinite continuous adaptivity, practically we achieved adaptivity ratios up to 5 orders of magnitude, while still being mass preserving and numerically stable, yielding unprecedented vivid surface detail at comparably low computational cost and moderate particle counts. |
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Paper Video The definitive Version was published in ACM Transactions on Graphics, https://doi.org/10.1145/3072959.3073713. |
| SCA 2016 - Constrained Neighbor Lists for SPH-based Fluid Simulations |
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| In this paper we present a new approach to create neighbor lists with strict memory bounds for incompressible Smoothed Particle Hydrodynamics (SPH) simulations. Our proposed approach is based on a novel efficient predictive-corrective algorithm that locally adjusts particle support radii in order to yield neighborhoods of a user-defined maximum size. Due to the improved estimation of the initial support radius, our algorithm is able to efficiently calculate neighborhoods in a single iteration in almost any situation. We compare our neighbor list algorithm to previous approaches and show that our proposed approach can handle larger particle numbers on a single GPU due to its strict guarantees and is able to simulate more particles in real time due to its benefits in regard to performance. Additionally we demonstrate the versatility and stability of our approach in several different scenarios, for example multi-scale simulations and with different kernel functions. |
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Paper Video |
| HPG 2016 - Adaptive Sampling for on-the-fly Rendering of Particle-Based Fluids |
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We present a fast and accurate ray casting technique for unstructured and dynamic particle sets. Our technique focuses on efficient, high quality volume rendering of fluids for computer animation and scientific applications. Our novel adaptive sampling scheme allows to locally adjust sampling rates both along rays and in lateral direction and is driven by a user-controlled screen space error tolerance. In order to determine appropriate local sampling rates, we propose a sampling error analysis framework based on hierarchical interval arithmetic. We show that our approach leads to significant rendering speed-ups with controllable screen space errors. Efficient particle access is achieved using a sparse view-aligned grid which is constructed on-the-fly without any pre-processing. |
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Paper Video |
| EuroVis 2015 - Vector Field Visualization of Advective-Diffusive Flows |
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We propose a framework for unified visualization of advective and diffusive concentration fluxes, which play a key role in many phenomena like, e.g. Marangoni convection and microscopic mixing. The main idea is the decomposition of fluxes into their concentration and velocity parts. Using this flux decomposition, we are able to convey advective-diffusive concentration transport using integral lines. In order to visualize superimposed flux effects, we introduce a new graphical metaphor, the stream feather, which adds extensions to stream tubes pointing in the directions of deviating fluxes. The resulting unified visualization of macroscopic advection and microscopic diffusion allows for deeper insight into complex flow scenarios that cannot be achieved with current volume and surface rendering techniques alone. Our approach for flux decomposition and visualization of advective-diffusive flows can be applied to any kind of (simulation) data if velocity and concentration data are available. We demonstrate that our techniques can easily be integrated into Smoothed Particle Hydrodynamics (SPH) based simulations. |
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Paper Video The definite version is available at onlinelibrary.wiley.com |
Research interests:
- Interactive simulation and rendering of SPH-based fluids
- Visualisation of advective-diffusive concentration transport
Teaching:
Sommersemester 2015: Computergraphik I
Sommersemester 2014: Computergraphik I
Wintersemester 2013/14: Computergraphik II
Sommersemester 2013: Computergraphik I