Game Development Reference
In-Depth Information
and the rock, grass, or dirt textures become stretched and distorted. A good rule of thumb is to keep the
highest peak one-ifth of the distance of your longest view, measured from the seabed or lowest terrain point.
That is, if you have a parcel 100 meters square, keep your highest peak at 40 meters (20 meters over the stan-
dard sea level of 20 meters). Also, remember that high mountains usually need big bases to look natural; the
land grade should start to rise from some distance away from the peak of the mountain.
5.3 METHODOLOGIES FOR TERRAFORMING USING HEIGHT MAPS
In larger-scale projects such as entire regions or grids, it is more eficient to utilize a height map to create
your landscape design. Height maps, or height ield maps as they are sometimes known, are powerful tools
for quickly creating lots of varied terrain. These are RGB (red, green, blue) images (256 by 256 pixels per
region) that deine the height of the terrain by the color values in the red channel. They are saved in the RAW
ile format, and although only 3 of the channels (red, green, and blue) actually affect the landscape now,
they still need to be saved with the legacy 13 channels to be loaded in properly in Second Life and OpenSim
through the viewer interface.
Note:
if you have your own region or grid in OpenSim with total server access,
then terrain manipulation can be accomplished with a simple 256 × 256 pixel grayscale image installed with
the “terrain load” server command. When you manipulate terrain with your bulldozer tool, you are actually
using “brushes” to change the values on an underlying height map, and those changes are interpreted by the
simulation program into changes in the elevations on your land surface patch.
5.3.1 r
egion
C
onTrols
for
T
errain
l
oading
and
T
exTures
Before we load in a dramatic example of how a height map works, let's look over the Region/Estate/Terrain
menu. You will ind it under World/Region Details in Firestorm.
Here are all the options on that menu; their location on the menu is indicated by number in Figure 5.6.
These are available to estate owners and managers:
1. Water Height is the setting that is your “sea level.” This is typically 20 meters from the bottom of
the sea, the lowest point on your land.
2. Terrain Raise Limit is the setting for your highest peak, above the baked default level set on the land.
3. Terrain Lower Limit is the setting for your lowest valley, or ocean bottom, below the baked default level.
4. Terrain Textures for the land surfaces are the dirt, grass, and rock textures applied to the terrain.
5. Texture Elevation Ranges is the location and range covered by these textures on the terrain.
6. Download RAW terrain … will allow you to download a RAW ile snapshot of your grayscale
height map onto your computer to be opened in a paint program such as Photoshop or GIMP (GNU
Image Manipulation Program).
7. Upload RAW terrain … will allow you to upload your preformatted RAW ile to the server and
install your new terrain. This is one of the most fun things to watch in a virtual world as the terrain
starts to ill in row by row.
Note
: Again, remember only owners have the rights to upload and
download terrain iles.
8. Bake Terrain freezes the present terrain as the middle level for the Terrain Raise and Lower limits.
5.3.2 e
xamining
a
B
enChmarK
T
errain
for
y
our
r
egion
Now, you have a general overview, let's proceed with the loading of your irst terrain. To prepare for the terrain
tests and projects in this chapter, you should now go to http://www.anncudworthprojects.com, and download
