Reducing the number of vertices in spheres:
Spheres are the most complex shapes that can be rendered, in other words
they have a lot of vertices, something you can't do much about unless you
don't use them. It is easy to make a sphere that has 100's and even 1000's
of vertices. What this means is LAG.when many are used in a small space.
But there are some ways to minimize that and situations where it won't matter.
If you use 3Dmax5 you are in luck, if you use the other 2 common modeling
program Wings3D and TS5.1, there is help too. The sphere that has the minimum
number of vertices is called a geodesic sphere. Buckminster Fuller brought
it to the public attention through his designs, the Epcot Dome in Disney
World is a perfect example of it. It is a sphere that consists of equal sized
triangles across the whole surface, as opposed to the usual sphere that has
many slices with triangles that get smaller toward the top and bottom.
In 3Dmax the primitive is called a geosphere and the number of segments
can be selected. A simple way to get a geodesic sphere into both Wings3D
and TS is too use the Renderware primitive called sphere, it is obvious that
the people who designed Renderware knew what they were doing. The script
is really simple and the following sample code will work for this. You don't
need to know any Renderware code, just copy the following code into notepad
or any editor and save it with the .rwx extension.
This will produce a sphere with a radius of 1m with 102 vertices and 200
triangles.
modelbegin
clumpbegin
sphere 1 5
clumpend
modelend |
It can't get any simpler that that and this could be combined with a model
made by a modeler program, but that is the topic of another tutorial. You
need a conversion program to import it into your modeler. The one I use is AccuTrans that
can read rwx files and convert them. After the file is converted to your
modeler you can use it the same as any other object.
As you can see by the picture below, I picked a sphere with 10 layers and
16 section to make the facing triangles about the same size as the geodesic
sphere. If you chose another variation, you mileage may vary as they say,
lol. Both will have the same smoothness in AW, but as you can see there is
a significant saving in triangles the other has 44% more triangles.
AW help http://www.activeworlds.com/help/aw34/rwx_sphere.html on
the sphere is short, it will not tell you how many vertices each sphere will
create as the second number increases. I have made a list for the first 10
numbers. My recommendation is to scale the number of triangles to the size
of the object, the larger the object the more triangles you can use. As you
may notice that the sphere has enough loops around it so it can easily be
split into half or quarter without adding any additional vertices doing so.
I all depends on the look you want. Items the size of an avatar hand can
be between 66 and 102
and the will look quite round when the lightsampling
vertex mode is enabled. When making domes 50m in size 1000 or more vertices
is probably about right, I think the AW gate sphere with 10,000 vertices (according
to ENZO) is overkill, even though it is 2 spheres, one inside the
other.
sphere 1 2 |
18 vertices |
sphere 1 2 |
18 vertices |
sphere 1 4 |
66 vertices |
sphere 1 5 |
102 vertices |
sphere 1 6 |
146 vertices |
sphere 1 7 |
198 vertices |
sphere 1 8 |
258 vertices |
sphere 1 9 |
326 vertices |
sphere 1 10 |
402 vertices |
sphere 1 16 |
1026 vertices |
