Abstract:
Finite element (FE) models are frequently used in engineering and life
sciences within time-consuming simulations. In contrast with the regular grid
structure facilitated by volumetric data sets, as used in medicine or
geosciences, FE models are defined over a non-uniform grid. Elements can have
curved faces and their interior can be defined through high-order basis
functions, which pose additional challenges when visualizing these models.
During ray-casting, the uniformly distributed sample points along each
viewing ray must be transformed into the material space defined within each
element. The computational complexity of this transformation makes a
straightforward approach inadequate for interactive data exploration. In this
paper, we introduce a novel coherency-based method which supports the
interactive exploration of FE models by decoupling the expensive
world-to-material space transformation from the rendering stage, thereby
allowing it to be performed within a precomputation stage. Therefore, our
approach computes view-independent proxy rays in material space, which are
clustered to facilitate data reduction. During rendering, these proxy rays
are accessed, and it becomes possible to visually analyze high-order FE
models at interactive frame rates, even when they are time-varying or consist
of multiple modalities. Within this paper, we provide the necessary
background about the FE data, describe our decoupling method, and introduce
our interactive rendering algorithm. Furthermore, we provide visual results
and analyze the error introduced by the presented approach.