5.4.1 Supported Operations

The implemented visualization operations which transform a given input into an output are characterized (by the relationships and restrictions of the dimensions of their respective input and output simplex sets) in Table 5.2. The input/output relationships are mostly implied by the abstract operation that is performed, whereas input (or output) limitations are mainly a matter of restricted implementation. In Table 5.2, ``n/a'' stands for not applicable, and a dash ``-'' stands for no restriction.

  
Table 5.2: Actually implemented generic visualization operations and their input/output requirements

Input

is the front-end data converter which typically converts PIF simulation data that contains geometrical structures as well as attributes defined on different grids into an appropriate simplex representation. Functionality for the decomposition of grid elements into simplexes is provided by the vista's GRid Support module (GRS). is the spatial dimension of the input geometry (or grid) and is the dimension of the attribute defined on it.

Transformation

performs a linear transformation on the point coordinates, of course without affecting the purely topological information (it also allows for a few common nonlinear operations).

Projection

always reduces the spatial dimension by 1 as it projects the simplex set onto an hyperplane.

Cut

constructs a -dimensional hypersurface. This can be used to obtain a geometrical cross-section as well as hypersurfaces for constant dependent variables (similar to orbitals).

Isolines

and Isoslices are two less generic but most often used modules that construct isolines and (coloured) slices of quasi-3d surfaces.

Vectors

creates short lines which symbolize vector fields (note the input requirement ).

Flowlines

extracts flowlines by piecewise analytical approximation from vector data.

Merge

merges simplex sets independent of their dimensions.

SVG-Output

converts the (immediately visualize-able) two-dimensional input simplex sets to SVG format, which is used as universal file format for simple two-dimensional vector graphics in VISTA.

NFF-Output

creates ray-tracing compatible NFF Neutral File Format file output which is understood by many ray-tracing and rendering packages.