The force fields used in molecular computational biology are not mathematically defined in such a way that their representation
would facilitate a straightforward application of volume visualization techniques. To visualize energy, it is necessary
to define a spatial mapping for these fields. Equipped with such a mapping, we can generate volume renderings of the internal energy states of a molecule. We describe our force field, the spatial mapping that we use for energy, and the visualizations that we produce from this mapping. We provide images and animations that offer insight into the computational behavior of the energy optimization algorithms that we employ.
Volume rendering requires the use of gradient information used as surface normal information, for application of lighting models. However, for interactive applications on- the-fly calculation of gradients is too slow. The common solution to this problem is to quantize gradients of trivariate scalar fields and pre-compute a look-up table prior to the application of a volume rendering method. A number of techniques have been proposed for the quantization of normal vectors, but few have been applied to or adapted for the purpose of volume rendering. We describe a new data- dependent method to quantize gradients using an even number of vectors in a table. The quantization scheme we use is based on a tessellation of the unit sphere. This tessellation represents an 'optimally' distributed set of unit normal vectors. Staring with a random tessellation, we optimize the size and distribution of the tiles with a simulated annealing approach.
Conference Committee Involvement (1)
Visualization and Data Analysis 2015
9 February 2015 | San Francisco, California, United States