NAME¶
r.out.vrml - Export a raster map to the Virtual Reality Modeling
Language (VRML)
KEYWORDS¶
raster, export, VRML
SYNOPSIS¶
r.out.vrml
r.out.vrml help
r.out.vrml elev=
string [
color=
string]
[
exag=
float]
output=
string [--
verbose]
[--
quiet]
Parameters:¶
- elev=string
-
Name of elevation map
- color=string
-
Name of color file
- exag=float
-
Vertical exaggeration
Default: 1.0
- output=string
-
Name for new VRML file
DESCRIPTION¶
This module exports a GRASS raster map to the Virtual Reality Modeling Language
(VRML) format for 3D visualization.
This version only outputs raster maps in VRML 1.0 format. The newer VRML 2.0
format will be more efficient for geographic applications, as it introduces an
"ElevationGrid" node so that only the elevation points will have to
be written instead of the whole geometry. The vast majority of VRML viewers
currently only support VRML 1.0. If the extension "wrl" (world) is
not present in the he
output parameter, it will be added.
WARNING¶
VRML is not well suited for large geometrys which can result from even a small
geographic region. Most viewers seem to bog down with more than 12,000
polygons, depending on your hardware & specific viewer. Each grid cell
results in two polygons, so a reasonable size region would be something less
than about 75x75. For improved performance and smaller file size, leave off a
color map. Since VRML is ascii text, gzip works very well to significantly
compress file size.
NOTE¶
This is a preliminary release of "
r.out.vrml". For further
information about VRML and available viewers for various platforms, see:
VRML Virtual Reality Modeling Language
BUGS:¶
Currently the region is transformed to a unit size, so real geographic location
is lost. Side effects when working in a lat-lon location are that besides
general distortion due to projection, a very small exaggeration factor (on
order of .001) must be used to compensate for vertical units expected to be
the same as map units.
TODO¶
Update to the more modern GeoVRML format, or probably better the next generation
X3D format. See also the Xj3D project.
Future plans for this module are to allow draping of sites objects and vector
maps and using the new sites format available in floating point GRASS to embed
WWW links into site objects. It will also be upgraded to support VRML 2.0 and
will allow entering multiple preset "views" using the existing GRASS
3d_view file format.
Other possible additions: Allow animation of elevation, color, or sites based on
user interaction. Degradation of the raster to produce TINs for improved
performance.
AUTHOR¶
Bill Brown, US Army Construction Engineering Research Laboratory
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
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