VRML
Forest Worlds
The
SFF uses the ray tracing program POVRAY and the Virtual Reaility
Modelling Language (VRML) as data visualization tools.
This page provides links to the VRML worlds we are creating.
Our VRML work is still "in beta". The worlds function properly,
but we have yet to add all of the features we want to see, such
as coarse woody debris and more realistic sky. Implementing
GZIP and expanding the number of worlds are also high priorities.
System
Requirements
- 1st
requirement: A VRML capable web browser. Most new "full
featured" browsers install VRML capability by default. This
link leads to a simple VRML tree. If your browser loads
a grey stick with a green cone on top, your browser will
load VRML worlds. If not, try visiting the Netscape or Microsoft
sites to acquire the needed software.
- Second
requirement is system speed. VRML is very system-demanding.
I suspect a Pentium is required minimum equipement, the
faster the better. I started developing on a system with
only 16 mb of RAM, and suffered lots of inexplicable crashes.
When I upgraded that system to 48 mb RAM, things ran much
more smoothly.
- Third
is patience. My 200 mhtz machine with 64 mb renders VRML
worlds S-L-O-W-L-Y as they first load. Once the scene is
up, you can move around quite quickly, but that first load
and render phase can take 5 minutes or more.
How
to View
Well, click on a link below. But you should know the following:
- Each
world has a series of cameras built in. If your VRML browser
has a "Views" button, click it a few times to get the guided
tour. Big VRML worlds can be hard to control when viewing
VRML worlds for the first time.
- Stay
away from the data links - the little white bands around
each tree that flash up an HTML reference when the cursor
touches them. They work just fine, BUT the whole scene has
to be re-rendered after you step out to view tree data.
A bit time consuming. You can put up with the wait to find
out more about an individual tree, or you can access the
whole data file for reference from the Main Data Link for
each scene.
- If
the trees are dark and dingy, locate your "lamp" control
and turn up the light level.
The
Worlds.....
Kennedy
Flats - Old Growth Coastal Plain Cedar Forest in Clayoquot Sound
- Test.
A single tree in the void - just to see if your VRML browser
is functioning.
- Medium.
A 113 k moderately sized world.
- Large.
A 301 k file with a much more "foresty" feel to it. The
largest scene my Pentium 120 is willing to handle reliably.
- The
Data. An HTML file of information for all of the trees
in the scene.
These files
are based on field infomration from the Kennedy Flats site which
we assessed for the
Clayoquot Symposium on Alternative Silvicultural Systems.
The Kennedy Flats forest is an ancient cedar stand growing on
a senstive, boggy area, with maratime clay soils with very slow
water drainage. The stand is very open, with scattered huge
cedars in poor health. The site is almost a forested bog. We
classified this site as ecologically sensitive, important fisheries
habitat, and unsuited for timber management.
And more worlds when I get the data run.........
These scenes are assemblages of WWWInLine images. I create one
Indexed-Face-Set polygon for the stem and another IFS for the
crown of each tree species present in the scene. (Files s_cw.wrl
and cw.wrl, for example.) These basic shapes are then referenced
as WWWInLines and transformed to correct height, length, diameter,
etc.to generate a crown and stem for each tree present in the
data set. (File cw111.wrl, for example.) A white disc as added
to the tree file to provide a data link to HTML files which
list the particulars of each tree. The main WRL file is in turm
a massive collection of WWWInLines which call up the individual
tree WRL's, and places them at the correct x,y,z coordinate
on the world plane.
The program renders in reverse order of construction. Therefore,
the field of view first fills with bounding boxes which approximate
the positions of individual trees. These are replaced (slowly)
with the more accurate bounding boxes which outline the component
stems and crowns of the individual trees. Finally, the system
penetrates all the way down to the master files which contain
the crown and stem IndexedFaceSets, and suddenly stems and crowns
appear all over the screen.
For
More Information, Contact:
Tom Bradley: tomatsilva@netidea.com
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