Sample Project Description
(NOTE: "Firm" and "Mentor" are not needed for regular in-house projects)
Student: Edward Delacruz
Firm: U.S. Army Topographic Engineering Center (TEC)
Mentor: Mr. Thomas Jorgensen
Title: Development of Three-Dimensional Terrain and Visualization Software
Background:
The primary purpose of TEC is to research and develop
topographic
techniques and equipment to aid soldiers in the field. The creation of
terrain
visualization software allows the commander to view realistic
three-dimensional
representations of probable battlefields. An area of "flying" over the
terrain.
Both dynamic and static three-dimensional models of land vehicles and
aircraft
can be inserted into this virtual environment to give a realistic feel to
the
region. Because the current system only allows for the display of actual
elevation data gathered by traditional methods, the objective of the project
is to develop a software program which did not rely on existing digital
topographic data, but would allow the user to construct the terrain.
Description:
Construction of a user-defined terrain requires some sort of
interface
that would translate human terminology for land features into numerical
data.
The computer uses a Digital Elevation Matrix (DEM), a two-dimensional array
which represents the terrain in a coordinate system. The row and column
index
numbers are the x and y coordinates, and the data within the element is the
elevation data or the z coordinate. The computer links these "flag" points
to
create a surface. In order to construct a terrain, the elements in the DEM
have
to be manipulated in a fashion that can translate human perception into
numerical
information. A critical portion of the project is to mathematically alter
the
DEM given user inputs such as land feature type (e.g. hills, ridges,
ditches,
plateaus), position, and height.
Being able to easily control construction is also a major aspect of the
program.
The project focuses on having mouse-based input because the keyboard can
sometimes
be cumbersome. The use of pop-up menus to select categorical data allows
information to be effortlessly chosen. Area and positioning of land
features
are inputted onto an overhead-view image giving the user visual feedback on
actual
location and size. Red lines drawn on the overhead-view image designate the
orientation of ditches and ridges while red rectangles illustrate the areas
where
hills and plateaus are placed. Shading of the overhead view gives the user
a
sense of where existing land features are located.
The final portion of the project is the creation of a visualization technique
that
makes the terrain look realistic. A lighting model is created that gives the
terrain a smooth, shaded appearance, which can be viewed by an infinite
number
of perspectives using a "fly" through method. The development of a function
that roughens a smooth terrain produces a natural-looking land surface.