Modeling

  The scope of this project requires modelling to be done by different
groups on different platforms, so the main focus of our portion of modeling
will be on providing translation schemes and utilities.  There are three
main areas for modeling in the virtual world.  The first area is
geographic and topological modeling, which provides the locations of all
buildings and the data used to produce the terrain when the agent is
outside.  The second area is modeling the buildings themselves.  Finally,
dynamic objects must be modeled.  Since SVE can read Alias/Wavefront's
OBJ files and because of Alias's availability on all the SGI's, it has
become the primary tool and file format to be used.


Topological Map Translation

  So far we have been given a topological map of Tech campus at a 4 foot
resolution, with heights quantized to fit in a 16 bit integer.  To 
translate the map into a usable mesh, the file is sampled on a grid.  After 
producing the grid of points, triangles are generated by dividing each 
square into an upper and lower triangle using  the top left and lower right
points.  This mesh data is then output into an OBJ file.  This procedure 
can be repeated on any raw map data as long as the format of the file is 
known.  There are several sources for topological data that could be used 
during this project.  Government GIS sources, for example, have elevation 
models for a wide variety of areas, and other spatial data.


Building Data
  
  We will most likely be getting most of our building data from
architecture firms and students.  The data will probably come in 
a variety of file formats which will need to be translated into OBJ's.  
Any internal modeling will be done in Alias/Wavefront to 
begin with.


Dynamic Objects

  Dynamic objects will likely be generated in a controlled manner, as it 
is likely that they will be created for specific projects in 
the future and to flesh out the world.  Because of this they will be done 
originally in OBJ format.


Conclusion

  Although the main concentration on the use of Alias/Wavefront has been that
SVE can natively read its output files, even if we scrapped the SVE 
based rendering engine the format is relatively popular and many 
conversion utilities exist for it.  Also, the interface is easier to learn 
than some other tools (3dmax, etc...) making the learning curve required for
worldbuilding less steep.