Topological Changes in Simulations of Deformable Objects
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Date
2017-04
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Université de Strasbourg and archives-ouvertes.fr
Abstract
Virtual cutting of deformable objects is at the core of many applications in
interactive simulation and especially in computational medicine. The ability
to simulate surgical cuts, soft tissue tearing or fractures, is essential for aug-
menting the capabilities of existing or future simulation systems.
In this thesis, we present a new remeshing algorithm based on the finite element
method. For tetrahedral elements with linear shape functions, we combined
remeshing algorithm with the movement of the nodes to the cutting surface,
called
snapping
in the literature. Our approach shows benefits when evaluat-
ing the impact of cuts on the number of nodes and the numerical quality of the
mesh. When applying our remeshing algorithm to quadratic shape functions,
we observe similar results. Due to the curved surfaces of the elements, when
using quadratic shape functions, the snapping of nodes entails higher chal-
lenges. Thus, to investigate into the snapping, experience has been gathered
on triangular shell elements, simulating fractures.
Beyond the simulation of fractures, our remeshing approach for tetrahedral
elements is generic enough to support a large variety of applications. In this
work, we are the first to present results on the detection of topological changes,
such as fractures, tearing and cutting, from a monocular video stream. Ex-
amples with highly elastic silicone bands, in-vivo livers and ex-vivo kidneys
show the robustness of our detection algorithm, which is combined with the
remeshing approach, in different scenarios. Finally, the augmentation of in-
ternal organ structures highlights the clinical potential and importance of the
conducted work.
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