Voxel-grid

Syntax:

    splot $voxelgridname with {dots|points} {above <threshold>} ...
    splot $voxelgridname with isosurface {level <threshold>} ...

Voxel data can be plotted with dots or points marking individual voxels whose value is above the specified threshold value (default threshold = 0). Color/pointtype/linewidth properties can be appended as usual.

At many view angles the voxel grid points will occlude each other or create Moiré artifacts on the display. These effects can be avoided by introducing jitter so that the displayed dot or point is displaced randomly from the true voxel grid coordinate. See set jitter (p. ).

Dense voxel grids can be down-sampled by using the pointinterval property (pi for short) to reduce the number of points drawn.

    splot $vgrid with points pointtype 6 pointinterval 2

with isosurface will create a tessellated surface in 3D enclosing all voxels with value greater than the requested threshold. The surface placement is adjusted by linear interpolation to pass through the threshold value itself.

See set vgrid (p. ), vfill (p. ). See demos vplot.dem, isosurface.dem.