Isosamples

The isoline density (grid) for plotting functions as surfaces may be changed by the set isosamples command.

Syntax:

     set isosamples <iso_1> {,<iso_2>}
     show isosamples

Each function surface plot will have 5#5iso_16#6 iso-u lines and 5#5iso_26#6 iso-v lines. If you only specify 5#5iso_16#6, 5#5iso_26#6 will be set to the same value as 5#5iso_16#6. By default, sampling is set to 10 isolines per u or v axis. A higher sampling rate will produce more accurate plots, but will take longer. These parameters have no effect on data file plotting.

An isoline is a curve parameterized by one of the surface parameters while the other surface parameter is fixed. Isolines provide a simple means to display a surface. By fixing the u parameter of surface s(u,v), the iso-u lines of the form c(v) = s(u0,v) are produced, and by fixing the v parameter, the iso-v lines of the form c(u) = s(u,v0) are produced.

When a function surface plot is being done without the removal of hidden lines, set samples controls the number of points sampled along each isoline; see set samples (p. ) and set hidden3d (p. ). The contour algorithm assumes that a function sample occurs at each isoline intersection, so change in samples as well as isosamples may be desired when changing the resolution of a function surface/contour.