plw3d - Configure the transformations required for projecting a 3D surface on a 2D window
Contents
Arguments
basex (PLFLT(3plplot), input) The normalized x coordinate size of the rectangular cuboid. basey (PLFLT(3plplot), input) The normalized y coordinate size of the rectangular cuboid. height (PLFLT(3plplot), input) The normalized z coordinate size of the rectangular cuboid. xmin (PLFLT(3plplot), input) The minimum x world coordinate of the rectangular cuboid. xmax (PLFLT(3plplot), input) The maximum x world coordinate of the rectangular cuboid. ymin (PLFLT(3plplot), input) The minimum y world coordinate of the rectangular cuboid. ymax (PLFLT(3plplot), input) The maximum y world coordinate of the rectangular cuboid. zmin (PLFLT(3plplot), input) The minimum z world coordinate of the rectangular cuboid. zmax (PLFLT(3plplot), input) The maximum z world coordinate of the rectangular cuboid. alt (PLFLT(3plplot), input) The viewing altitude in degrees above the xy plane of the rectangular cuboid in normalized coordinates. az (PLFLT(3plplot), input) The viewing azimuth in degrees of the rectangular cuboid in normalized coordinates. When az=0, the observer is looking face onto the zx plane of the rectangular cuboid in normalized coordinates, and as az is increased, the observer moves clockwise around that cuboid when viewed from above the xy plane.
Description
Configure the transformations required for projecting a 3D surface on an existing 2D window. Those
transformations (see the PLplot documentation) are done to a rectangular cuboid enclosing the 3D surface
which has its limits expressed in 3D world coordinates and also normalized 3D coordinates (used for
interpreting the altitude and azimuth of the viewing angle). The transformations consist of the linear
transform from 3D world coordinates to normalized 3D coordinates, and the 3D rotation of normalized
coordinates required to align the pole of the new 3D coordinate system with the viewing direction
specified by altitude and azimuth so that x and y of the surface elements in that transformed coordinate
system are the projection of the 3D surface with given viewing direction on the 2D window.
The enclosing rectangular cuboid for the surface plot is defined by xmin, xmax, ymin, ymax, zmin and zmax
in 3D world coordinates. It is mapped into the same rectangular cuboid with normalized 3D coordinate
sizes of basex by basey by height so that xmin maps to -basex/2, xmax maps to basex/2, ymin maps to
-basey/2, ymax maps to basey/2, zmin maps to 0 and zmax maps to height. The resulting rectangular cuboid
in normalized coordinates is then viewed by an observer at altitude alt and azimuth az. This routine
must be called before plbox3(3plplot) or any of the 3D surface plotting routines; plmesh(3plplot),
plmeshc(3plplot), plot3d(3plplot), plot3dc(3plplot), plot3dcl(3plplot), plsurf3d(3plplot),
plsurf3dl(3plplot) or plfill3(3plplot).
Redacted form: plw3d(basex,basey,height,xmin,xmax,ymin,ymax,zmin,zmax,alt,az)
This function is examples 8, 11, 18, and 21.
Name
plw3d - Configure the transformations required for projecting a 3D surface on a 2D window
See Also
PLplot documentation at http://plplot.org/documentation.php.
July, 2025 PLW3D(3plplot)
Synopsis
plw3d(basex, basey, height, xmin, xmax, ymin, ymax, zmin, zmax, alt, az)
