Problem: ARCTIN with POLY option can hang with some datasets
TINs with very complex data area definitions may cause TINARC with the POLY option to hang.
This is a known limit.
Solution or Workaround
Temporarily rename the tmsk and tmsx files in the TIN folder then run TINARC. This will output ALL triangles as polygons, including triangles that are outside the hull (interpolation zone).
Restore the names of the tmsk and tmsx files. Run TINARC again using the HULL option.
Use other workstation tools to select and preserve only those triangles that reside within the hull. For example, you can use ARCPLOT's RESELECT OVERLAP WITHIN to generate a writeselect file for use with ARC RESELECT.
Alternately, you can use customization in the Desktop COM environment. The 3D Analyst TIN class provides low level access to the TIN data structure. Looping through all data triangles and writing them out to a feature class will produce the equivalent result.