NAME      READ_TIN - Reader for Arc/Info Triangulated Region Mesh

AUTHOR    Scott Goodyear

TYPE      Input

INPUTS
    TIN (Arc/Info) file
    "Texture" field 2D 2-space 4-vector uniform byte OPTIONAL

OUTPUTS
    "Geometry" geom Polyhedron, with imbedded texture field

PARAMETERS

    "TinFile" TIN file name browser

    "ZScale" dial 1.00000 0.00000 100.000  (Z Exaggeration on mesh)

    "WorldImageFile" file name browser for World Mapping File

    "AutoTransform" boolean - controls coordinate representation

    "ZeroElevations" boolean - creates flat version of TIN

DESCRIPTION

The READ_TIN module accesses external ASCII files defining
a triangulated irregular network (TIN) structure from Arc/Info.
This is generally used for a surface representation derived from
irregulary space sample points and breakline features. The TIN data
set includes topological relationships between points and their proximal
triangles. Each sample point has an x,y coordinate and a surface,
or z-value. These points are connected by edges to form a set of
nonoverlapping triangles userd to represent the surface.
TIN files are also called "irregular triangular mesh" or
"irregular triangular surface model" in some contexts.
"TIN" is the name of the ESRI Arc/Info application module that models,
creates, displays, and exports TIN files.

Within the TIN application the UNGENERATETIN command with the NET option
should generate files compatable with this reader module.

An optional image input port will apply a full colour texture map
onto the TIN geometry, such that the geometry viewer can show the texture
overlay on the terrain.

The second file browser (WorldImageFile) allows a small
coordinate range correction file
to specify the mapping between the optional input raster texture image
and the TIN coordinate system.

This module requires AVS 5.01, with texture per object support.