31 research outputs found
Analysis of a Reduced-Order Model for the Simulation of Elastic Geometric Zigzag-Spring Meta-Materials
We analyze the performance of a reduced-order simulation of geometric
meta-materials based on zigzag patterns using a simplified representation. As
geometric meta-materials we denote planar cellular structures which can be
fabricated in 2d and bent elastically such that they approximate doubly-curved
2-manifold surfaces in 3d space. They obtain their elasticity attributes mainly
from the geometry of their cellular elements and their connections. In this
paper we focus on cells build from so-called zigzag springs. The physical
properties of the base material (i.e., the physical substance) influence the
behavior as well, but we essentially factor them out by keeping them constant.
The simulation of such complex geometric structures comes with a high
computational cost, thus we propose an approach to reduce it by abstracting the
zigzag cells by a simpler model and by learning the properties of their elastic
deformation behavior. In particular, we analyze the influence of the sampling
of the full parameter space and the expressiveness of the reduced model
compared to the full model. Based on these observations, we draw conclusions on
how to simulate such complex meso-structures with simpler models.Comment: 14 pages, 12 figures, published in Computers & Graphics, extended
version of arXiv:2010.0807
Topology-Aware Surface Reconstruction for Point Clouds
We present an approach to inform the reconstruction of a surface from a point
scan through topological priors. The reconstruction is based on basis functions
which are optimized to provide a good fit to the point scan while satisfying
predefined topological constraints. We optimize the parameters of a model to
obtain likelihood function over the reconstruction domain. The topological
constraints are captured by persistence diagrams which are incorporated in the
optimization algorithm promote the correct topology. The result is a novel
topology-aware technique which can: 1.) weed out topological noise from point
scans, and 2.) capture certain nuanced properties of the underlying shape which
could otherwise be lost while performing surface reconstruction. We showcase
results reconstructing shapes with multiple potential topologies, compare to
other classical surface construction techniques, and show the completion of
real scan data
Sampling Gabor noise in the spatial domain
Figure 1: Examples of a snake model with Gabor noise sampled on it. The bottom row shows the noise components and the control maps used to weight particular parameters of the noise. The left-most example shows standard Gabor noise, in the middle the frequency of the harmonic is weighted by a hat-profile, and in the right example the noise scale and the frequency are weighted by respective profiles. In all three cases the noise is evaluated in the modelās uv-domain. Gabor noise is a powerful technique for procedural texture gener-ation. Contrary to other types of procedural noise, its sparse con-volution aspect makes it easily controllable locally. In this paper, we demonstrate this property by explicitly introducing spatial vari-ations. We do so by linking the sparse convolution process to the parameterization of the underlying surface. Using this approach, it is possible to provide control maps for the parameters in a natural and convenient way. In order to derive intuitive control of the re-sulting textures, we accomplish a small study of the influence of the parameters of the Gabor kernel with respect to the outcome and we introduce a solution where we bind values such as the frequency or the orientation of the Gabor kernel to a user-provided control map in order to produce novel visual effects