by I'm doing an MSEE thesis on generating a hierarchical multiresolution
terrain data base from Digital Terrain Elevation Data (DTED, regularly
sampled elevation posts). I generate polygons (actually triangles) that
would be used by an image generation system to drape texture over them
and render a scene (maybe for flight simulation). The generation of the
data base of triangles is an offline process. It is hierarchical in
that the root of the tree of triangles is the coarsest representation
(large triangles with relatively large maximum height error). The
next branch of the tree splits parent triangles to create a representation
with a smaller maximum height error. This is continued to reach a desired
accuracy. I concern myself with maintaining a continuous surface (i.e,
no holes), triangles that are not "too slivery" (i.e., long & thin),
and minimum number of triangles required for desired maximum height
error.
The idea is that a scene could be rendered by mosaic-ing triangles
from different depths in the data base depending on the required
accuracy. For terrain at the horizon the coarsest representation
could be used. For terrain closer to the eyepoint, a finer
representation could be used.
I believe that two factors in this process are:
1) Filtering the data to avoid aliasing (I'm using a Wavelet
based filtering process).
2) The acutal triangulation method (currently using a
quaternary triangulation scheme, split a triangle
into four by joining a point along each edge).
My question: Is this (i.e., generating triangles from elevation
posts to be used for scene rendering) considered a solved problem?
Would someone actually use this type of data base?
I'm particularly interested in responses from those users of
high end machines, like SGIs. But please don't reserve
responses/opinions to that perspective.
thanks for your time,
Robert Fuentes
(The University of Texas at Arlington)
Lockheed Martin