can a 3-D shapefile be turned into a TIN in order to interact with a raster?

Discussion created by abigail_gleason on Oct 18, 2013

   I'm new to using 3-D shapefiles and so far I haven't been able to find a methodology for what I'm trying to do. I have a 3-D shapefile that I would like to use as a surface.  I also have a DEM, and I would like to determine what areas of the DEM are above the surface and what areas are below.  My thought is that if I could turn the 3-D shapefile into a TIN, a simple difference between the TIN and the DEM may work. However, the height information of each verticie in the 3-D shapefile is not discoverable as far as I can tell (though I have not tried extracting the information via a python script yet, I thought there should be an easier way), and in any case the height information may be relative and not represented as a mean sea level height or ellipsoid height.
Therefore, is there a methodology in place to discover the height information from a 3-D shapefile, edit that height information (to give it an MSL or ellipsoid height), and turn the 3-D shapefile into a TIN? Or is there an easier way to accomplish what I'm trying to do?
Any help would be appreciated.
Thank you,