Deforming Meshes that Split and Merge
Abstract
We present a method for accurately tracking the moving surface of
deformable materials in a manner that gracefully handles topological
changes.We employ a Lagrangian surface tracking method, and
we use a triangle mesh for our surface representation so that fine
features can be retained. We make topological changes to the mesh
by first identifying merging or splitting events at a particular grid
resolution, and then locally creating new pieces of the mesh in the
affected cells using a standard isosurface creation method.We stitch
the new, topologically simplified portion of the mesh to the rest of
the mesh at the cell boundaries. Our method detects and treats topological
events with an emphasis on the preservation of detailed features,
while simultaneously simplifying those portions of the material
that are not visible. Our surface tracker is not tied to a particular
method for simulating deformable materials. In particular,
we show results from two significantly different simulators: a Lagrangian
FEM simulator with tetrahedral elements, and an Eulerian
grid-based fluid simulator. Although our surface tracking method is
generic, it is particularly well-suited for simulations that exhibit fine
surface details and numerous topological events. Highlights of our
results include merging of viscoplastic materials with complex geometry,
a taffy-pulling animation with many fold and merge events,
and stretching and slicing of stiff plastic material.
Wojtan, C., Thürey, N., Gross, M., and Turk, G. Deforming Meshes that Split and Merge. SIGGRAPH 2009.