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structured_grid_set(visage) VISAGE structured_grid_set(visage)

NAME

structured_grid_set - VISAGE geometry data for structured grids.

DESCRIPTION

The structured_grid_set object represents geometry as an implicitly ordered array of points. The points are topologically regular forming hexahedral cells. The points are defined as triplets of x,y,z values.

There are three ways to create the structured grid data:

1 using scripts (use the data=, data+ methods from visage_data superclass),

2 using the plot3d reader,

3 or using the netCDF reader.

The examples in this man page show how to create a structured grid using a script. For large data sets, however, this is impractical and one of the reader objects should be used.

SUPERCLASS

visage_abstract_geometry

INSTANCE VARIABLES

dimensions the number of points in the i,j,k topological dimensions. The total number of points is given by i*j*k.

MESSAGES

number_points?/no_points? return the number of points in the grid.

cell_points! internal method to compute cell point id's from current cell, origin, aspect ratio, and dimensions.

cell_coords! internal method to compute cell coordinates from current cell, origin, aspect ratio, and dimensions.

point_cells! find all the cells that use a particular point.

number_cells! compute the number of cells in the volume.

cell_neighbor! get the neighbor to the current cell given the

current cell and parametric coordinates.

location! compute the location of a x-y-z point from an initial position. The location is the cell number plus the parametric coordinates (r-s-t) in the cell.

location_to_cell! convert a location in the form of (i.r,j.s,k.t) to a cell numer plus a parametric coordinate (r,s,t).

position! compute the position of a point from the cell number and parametric coordinates.

output! bformatted print (using unix command more) of data values.

EXAMPLE

The following example creates a structured grid of dimensions 2x3x4 with associated data.

/* * Create structured grid */ structured_grid_set new: grid dimensions= (2,3,4); grid data=(0., 0., 0., 1., 0., 0., 0., 1., 0., 1., 1., 0., 0., 2., 0., 1., 2., 0.) data+(0., 0., 1., 1., 0., 1., 0., 1., 1., 1., 1., 1., 0., 2., 1., 1., 2., 1.) data+(0., 0., 2., 1., 0., 2., 0., 1., 2., 1., 1., 2., 0., 2., 2., 1., 2., 2.) data+(0., 0., 3., 1., 0., 3., 0., 1., 3., 1., 1., 3., 0., 2., 3., 1., 2., 3.) ; /* * Vector data */ visage_vector new: velocity; velocity data= (0., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) data+ (1., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) data+ (2., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) data+ (2., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) data+ (2., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) data+ (3., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) ; /* * Scalar data */ visage_scalar new: pressure;

pressure data=(0., 0., 0., 1., 0., 0., 0., 2., 0., 0., 0., 3.) data+ (1., 1., 1., 2., 1., 1., 3., 2., 1., 1., 1., 3.) ; /* * Create a data set */ visage_data_set new: adata_set geometry= grid scalar_data= pressure vector_data= velocity ; /* * Now create a visual image */ /* * Create an outline */ data_outline new: an_outline data_in= adata_set generate_data! ; display_lines new: draw_outline data_in= an_outline ; actor new: outline_actor modeller=draw_outline ; /* * Create a geometry */ data_geometry new: a_geometry extent=(1,1,1,3,1,4) data_in= adata_set ; display_surface new: draw_surface data_in= a_geometry ; actor new: geometry_actor modeller=draw_surface ; /* * Create an iso-surface */ data_iso_surface new: iso value=2.0 data_in= adata_set ; display_all new: draw_iso data_in= iso ; actor new: iso_actor modeller=draw_iso ;

/* * Render the image */ renderer new: aren actors= [actor instances?] render! ;