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Richard Keiser, Markus Gross
In this project we develop particle-based Lagrangian methods for simulating
elasto-plastic solids, as well as fluids and phase transitions between
solids and fluids like melting and freezing. The use of particles instead
of a volumetric mesh has several advantages. For solids, the sampling of
the volume of a given object is very simple in comparison to the generation
of a mesh. Furthermore, during plastic deformation, the object can deviate
substantially from its original configuration and even change its topology.
In this case, a particle representation is better suited then a mesh with fixed
connectivity. For fluids, advection is very simple using a Lagrangian method
compared with standard Eulerian methods, as the material properties move
together with the particles. Furthermore, mass conservation is trivially
fulfilled and the method does not suffer from dissipation. Finally, using
a particle-based Lagrangian approach enables to combine deformable solids
and fluids into one framework, which allows simulating phase transition such
as melting and freezing, as well as combining solid and fluid characteristics
to goop-like viscoelastic materials such as clay and mucus.
By using points not only for representing the volume but also for the surface
we have a very flexible framework at hand with which we can handle both highly
detailed surfaces as well as large deformations and topological changes. We exploit
this combination for fracturing both rigid and ductile materials, the simulation of
thin shells that fracture, and melting and freezing of objects.
Finally, we are working on unconditionally stable animation of deformable objects
using explicit integration. This is achieved by fitting the original configuration
of points (the rest state) to the deformed configuration after an animation step
using shape matching techniques. The fitted rest shape yields goal positions for
all points. We show that by pulling the animated points towards the goal positions,
the animation is unconditionally stable.
Algebraic Point Set Surfaces (APSS) define a smooth surface from a set of points
using local moving least-squares (MLS) fitting of algebraic spheres. We first revisit
the spherical fitting problem and provide a new, more generic solution that includes
intuitive parameters for curvature control of the fitted spheres. As a second
contribution we present a novel real-time rendering system of such surfaces
using a dynamic up-sampling strategy combined with a conventional splatting
algorithm for high quality rendering. Our approach also includes a new view
dependent geometric error tailored to efficient and adaptive up-sampling of
the surface. One of the key features of our system is its high degree of
flexibility that enables us to achieve high performance even for highly dynamic
data or complex models by exploiting temporal coherence at the primitive level.
We also address the issue of efficient spatial search data structures with
respect to construction, access and GPU friendliness. Finally, we present
an efficient parallel GPU implementation of the algorithms and search structures.
- M. Wicke, D. Steinemann, M. Gross, Efficient Animation of Point-Sampled Thin Shells, Proceedings of Eurographics '05, pp. 667-676 (Dublin, Ireland, Aug 29th - Sep 2nd, 2005)
[Abstract]
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- B. Adams, R. Keiser, M. Pauly, L. J. Guibas, M. Gross, P. Dutré, Efficient Raytracing of Deforming Point-Sampled Surfaces, Proceedings of Eurographics 2005, pp. 677-684 (Dublin, Ireland, August 29 - September 3, 2005)
[Abstract]
[PDF] [Video]
- R. Keiser, B. Adams, D. Gasser, P. Bazzi, P. Dutré, M. Gross, A Unified Lagrangian Approach to Solid-Fluid Animation, Proceedings of the Symposium on Point-Based Graphics 2005, pp. 125-133 (Stony Brook, USA, June 21-22)
[Abstract]
[PDF] [Video] [Video] [Video] [Video] [Video]
- M. Pauly, R. Keiser, B. Adams, P. Dutré, M. Gross, L. J. Guibas, Meshless Animation of Fracturing Solids, Proceedings of ACM SIGGRAPH 2005 (Los Angeles, USA, July 31 - August 4, 2005), pp. 957-964
[Abstract]
[PDF] [Video]
- M. Müller, B. Heidelberger, M. Teschner, M. Gross, Meshless Deformations Based on Shape Matching, Proceedings of ACM SIGGRAPH 2005 (Los Angeles, USA, July 31 - August 4, 2005), pp. 471-478
[Abstract]
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- M. Müller, B. Solenthaler, R. Keiser, M. Gross, Particle-Based Fluid-Fluid Interaction, Proceedings of the Eurographics Symposium on Computer Animation 2005 '05, pp. 237-244 (Los Angeles, USA, July 29 - 31, 2005)
[Abstract]
[PDF] [Video] [Video] [Video] [Video]
- M. Pauly, D. K. Pai, L. J. Guibas, Quasi-Rigid Objects in Contact, ACM Siggraph/Eurographics Symposium on Computer Animation 2004
[PDF]
- R. Keiser, M. Müller, B. Heidelberger, M. Teschner, M. Gross, Contact Handling for Deformable Point-Based Objects, Proceedings of Vision, Modeling, Visualization '04, p.315-322 (VMV'04, Stanford, USA, November 16-18, 2004)
[Abstract]
[PDF] [Video]
- M. Müller, R. Keiser, A. Nealen, M. Pauly, M. Gross, M. Alexa, Point Based Animation of Elastic, Plastic and Melting Objects, Proceedings of ACM SIGGRAPH / Eurographics Symposium on Computer Animation 2004, p. 141-151 (ACM SIGGRAPH / Eurographics Symposium on Computer Animation (SCA 2004), Genoble, France, August 27-29, 2004)
[Abstract]
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- M. Müller, S. Schirm, M. Teschner, B. Heidelberger, M. Gross, Interaction of Fluids with Deformable Solids, Proceedings of Computer Animation and Virtual Worlds (CAVW), pp. 159-171 (CASA 2004, Geneva, Switzerland, July 7-9, 2004)
[Abstract]
[PDF] [Video] [Video] [Video] [Video]
- M. Müller, S. Schirm, M. Teschner, Interactive Blood Simulation for Virtual Surgery Based on SPH, Journal of Technology and Health Care, vol. 12, no. 1, 2004, pp. 25-31
[Abstract]
[PDF]
- M. Müller, D. Charypar, M. Gross, Particle-Based Fluid Simulation for Interactive Applications, Proceedings of ACM SIGGRAPH / EG Symposium on Computer Animation 2003, D. Breen, M. Lin (eds.), ACM NY, pp. 154-159 (ACM SIGGRAPH / EG Symposium on Computer Animation 2003, San Diego, CA, USA, July 26-27, 2003)
[Abstract]
[PDF] [Video]
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