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@PHDTHESIS{Jerbkov:62528,
author = {Jerábková, Lenka},
othercontributors = {Bischof, Christian},
title = {{I}nteractive cutting of finite elements based deformable
objects in virtual environments},
address = {Aachen},
publisher = {Publikationsserver der RWTH Aachen University},
reportid = {RWTH-CONV-124092},
pages = {92 S. : Ill., graph. Darst.},
year = {2007},
note = {Zsfassung in dt. und engl. Sprache; Aachen, Techn.
Hochsch., Diss., 2007},
abstract = {There is a wide range of virtual reality (VR) applications
that benefit from physically based modeling, such as
assembly simulation, robotics, training and teaching (e.g.,
medical, military, sports) and entertainment. The dynamics
of rigid bodies is well understood and several open source
as well as commercial physics engines supporting articulated
rigid bodies and particle systems are available. On the
other hand, the simulation of deformable bodies is an
objective of current research. The main application areas of
deformable objects simulation in computer graphics and VR
are the simulation of cloth and medical simulation. The
challenge of VR applications is the real time simulation
requirement. The raising computational power of the last
decades allowed for adapting selected methods known from
engineering sciences for interactive simulation. The
simulation of cutting is especially challenging though, as
most methods suffer from both performance and stability
issues. Although a number of approaches have been presented
over the last decade, the problem has not been solved
satisfyingly, yet. This thesis presents methods for an
interactive simulation of finite elements based deformable
objects as used, e.g., in VR surgical simulators. The main
objectives of such simulators are stability and performance
of the employed methods allowing for an interactive object
manipulation including topological changes in real time. A
novel method for interactive cutting of deformable objects
in virtual environments is presented. The key to this method
is the usage of the extended finite elements method (XFEM).
The XFEM can effectively model discontinuities within an FEM
mesh without creating new mesh elements and thus minimizing
the impact on the performance of the simulation. The XFEM
can be applied to advanced constitutive models used for the
interactive simulation of large deformations. Moreover, an
analysis of mass lumping techniques, showing that the
stability of the simulation is guaranteed even when small
portions of the material are cut is presented. The XFEM
based cutting surpasses the currently most widely used
remeshing methods in both, performance and stability and is
suitable for interactive VR simulation. Further, a software
architecture for physical simulation of deformable objects
in VR applications is proposed. The framework is suitable
for the creation of complex VR applications as, e.g., a
virtual surgical trainer. It uses thread level task
parallelization for the concurrent execution of
visualization, collision detection, haptics and deformation.
Moreover, a parallelization approach for the deformation
algorithm, which is the most computationally intensive part
is proposed. The presented solution based on OpenMP requires
only minimal changes to the source code while achieving a
speedup comparable to the results of more sophisticated
approaches. The presented framework benefits from the
current developments in the computing industry and allows an
optimal utilization of multicore CPUs.},
keywords = {Virtuelle Realität (SWD) / Finite-Elemente-Methode (SWD)},
cin = {124170 / 120000},
ddc = {004},
cid = {$I:(DE-82)124170_20140620$ / $I:(DE-82)120000_20140620$},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:hbz:82-opus-20943},
url = {https://publications.rwth-aachen.de/record/62528},
}
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