Recent developments in analyzing molecular structures and representing
solid models using simplicial complexes have further enhanced the nee
d for computing structural information about simplicial complexes in R
-3. This paper develops basic techniques required to manipulate and an
alyze structures of complexes in R-3. A new approach to analyze simpli
cial complexes in Euclidean 3-space R-3 is described. First, methods f
rom topology are used to analyze triangulated 3-manifolds in R-3. Then
, it is shown that these methods can, in fact, be applied to arbitrary
simplicial complexes in R-3 after (simulating) the process of thicken
ing a complex to a 3-manifold homotopic to it. As a consequence consid
erable structural information about the complex can be determined and
certain discrete problems solved as well. For example, it is shown how
to determine the homology groups, as well as concrete representations
of their generators, for a given complex in R-3.