NAME

r.out.pov - Converts a raster map layer into a height-field file for POVRAY.

 (GRASS Raster Data Export Program)

SYNOPSIS

r.out.pov
r.out.pov help
r.out.pov [-h] map=name tga=name [hftype=value] [bias=value] [scale=value]

DESCRIPTION

r.out.pov converts a user-specified raster map layer (map==name) into a height-field file for POVray (tga==name). The hftype==value option (where value is either 0 or 1) specifies the height-field type. When the user enters 0 the output will be actual heights. If entered 1 the cell-values will be normalized. If hftype is 0 (actual heights) the bias==value can be used to add or substract a value from heights. Use scale==value to scale your heights by value. The GRASS program r.out.pov can be used to create height- field files for Persistence of Vision (POV) raytracer. POV can use a height-field defined in Targa (.TGA) image file format where the RGB pixel values are 24 bits (3 bytes). A 16 bit unsigned integer height-field value is assigned as follows: RED = high byte, GREEN = low byte, BLUE = empty.

 

Parameters:

map=name Name of an existing raster map layer.

 tga=name Name of TARGA outputfile (one should add the extension .tga).

 hftype=value 0=actual heights, 1=normalized heights.

 bias=value Bias which is added or substracted to heights.

 scale=value Value to stretch or shrink elevations.

 r.out.pov can be run either non-interactively or interactively. The program will be run non-interactively if the user specifies the name of a raster map layer and a name for tga (output), using the form

                     r.out.pov map=inname tga=outname

 where inname is the name of a raster map layer to be converted to POV format, and outname is the name of the outputfile. Further optional values can be entered.

 Alternately, the user can simply type r.out.pov on the command line, without program arguments. In this case, the user will be prompted for parameter values using the standard GRASS parser interface described in the manual entry for parser.

                    r.out.pov map=elevation tga=out.tga

EXAMPLE

An example Povray script file may look like this: 

#include "shapes.inc"
#include "colors.inc"
#include "textures.inc"

#declare Scale = 7;

light_source { <40000, Scale*3000, 5000> color MainLight }
 
camera {
   location < 23000, Scale*2000, 0>
   angle  90
   look_at < 23000, Scale*1400, 5000>
}
 
height_field  {
   tga "dem.lr.tga"
   smooth
   water_level 0.11  // 726 / 6553.6 = 0.111
    texture {
      pigment {
          image_map { // image is always projected from -z, with front facing  +z, top to +Y
             ppm "map.lr.ppm"
             once
          }
          rotate x*90 // align map to height_field
      }
    }
   finish {
          ambient 0.2         // Very dark shadows
          diffuse 0.8         // Whiten the whites
          phong 0.2           // shiny
          phong_size 100.0    // with tight highlights
          specular 0.5
          roughness 0.05
   }
   scale < 14500, Scale*6553.6, 13000 >
   translate <18300, 0, 1100>
}

AUTHOR

Klaus Meyer, GEUM.tec GbR, eMail: GEUM.tec@geum.de
 

NOTICE

This program is part of the contrib section of the GRASS distribution. As such, it is externally contributed code that has not been examined or tested by the Office of GRASS Integration.

Last changed: $Date$