Author: Bender, Jan × Start date: 2006 × End date: 2009 × Has files: true ×

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    Fast Dynamic Simulation of Multi-Body Systems Using Impulses
    (The Eurographics Association, 2006) Bender, Jan; Schmitt, Alfred A.; Cesar Mendoza and Isabel Navazo
    A dynamic simulation method for multi-body systems is presented in this paper. The special feature of this method is that it satisfies all given constraints by computing impulses. In each simulation step the joint states after the step are predicted. In order to obtain valid states after the simulation step, impulses are computed and applied to the connected bodies. Since a valid joint state is targeted exactly, there is no drift as the simulation proceeds in time and so no additional stabilisation is required. In previous approaches the impulses for a multi-body system were computed iteratively. Since dependencies between joints were not taken into account, the simulation of complex models was slow. A novel method is presented that uses a system of linear equations to describe these dependencies. By solving this typically sparse system the required impulses are determined. This method allows a very fast simulation of complex multi-body systems.
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    Parallel Simulation of Inextensible Cloth
    (The Eurographics Association, 2008) Bender, Jan; Bayer, Daniel; Francois Faure and Matthias Teschner
    This paper presents an efficient simulation method for parallel cloth simulation. The presented method uses an impulse-based approach for the simulation. Cloth simulation has many application areas like computer animation, computer games or virtual reality. Simulation methods often make the assumption that cloth is an elastic material. In this way the simulation can be performed very efficiently by using spring forces. These methods disregard the fact that many textiles cannot be stretched significantly. The simulation of inextensible textiles with methods based on spring forces leads to stiff differential equations which cause a loss of performance. In contrast to that, in this paper a method is presented that simulates cloth by using impulses. The mesh of a cloth model is subdivided into strips of constraints. The impulses for each strip can be computed in linear time. The strips that have no common particle are independent from each other and can be solved in parallel. The impulse-based method allows the realistic simulation of inextensible textiles in real-time.
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    Volume Conserving Simulation of Deformable Bodies
    (The Eurographics Association, 2009) Diziol, Raphael; Bender, Jan; Bayer, Daniel; P. Alliez and M. Magnor
    We present a new method for simulating volume conserving deformable bodies using an impulse-based approach. In order to simulate a deformable body a tetrahedral model is generated from an arbitrary triangle mesh. All resulting tetrahedrons are assigned to volume constraints which ensure the conservation of the total volume. For the simulation of such a constraint impulses are computed and applied to the particles of the assigned tetrahedrons. The algorithm is easy to implement and ensures exact volume conservation in each simulation step.
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    Optimized Impulse-Based Dynamic Simulation
    (The Eurographics Association, 2009) Bayer, Daniel; Diziol, Raphael; Bender, Jan; Hartmut Prautzsch and Alfred Schmitt and Jan Bender and Matthias Teschner
    The impulse-based dynamic simulation is a recent method to compute physically based simulations. It supports the simulation of rigid-bodies and particles connected by all kinds of implicit constraints. In recent years the impulse-based dynamic simulation has been more and more used to simulate deformable bodies as well. These simulations create new requirements for the runtime of the method because very large systems of connected particles have to be simulated to get results of high quality. In this paper several runtime optimizations for the impulse-based dynamic simulation are presented. They allow to compute the same simulations at a fraction of time needed for the original method. Therefore, larger systems or simulations with increased accuracy can be simulated in realtime.
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    Simulating Almost Incompressible Deformable Objects
    (The Eurographics Association, 2009) Diziol, Raphael; Bayer, Daniel; Bender, Jan; Hartmut Prautzsch and Alfred Schmitt and Jan Bender and Matthias Teschner
    We present a new method for simulating almost incompressible deformable objects. A tetrahedral model is used to represent and restore the volume during the simulation. A new constraint, which computes impulses in the one-ring of each vertex of the tetrahedral model, is used in order to conserve the initial volume. With different parameters, the presented method can handle a large variety of different deformation behaviors, ranging from stiff to large deformations and even plastic deformations. The algorithm is easy to implement and reduces the volume error to less than 1 percent in most situations, even when large deformations are applied.