create a boundary for Geopack TIN create a boundary for Geopack TIN tanya20 (Civil/Environmental) (OP) 10 Jul 08 12:46 Using GEOPACK. How to create a TIN boundary to build a TIN and contours based on survey points. I do not want to use all the points from my .ASC file. I can't figure out how to build the boundary RE: create a boundary for Geopack TIN sam74 (Civil/Environmental) 10 Jul 08 13:02 Write all of the spots out into a dgn file. Then using dtm tools go to extract graphics. Set file open to create and feature to spots. At the bottom left hand corner of this box click on the box under extract. You can set it to view, fence, or complex chain whichever you decide to use as a boundary for your .dat file. Draw your boundary hit the reset button and then the match button and click on the spots and click apply.then go to dtm tools build and convert your newly create .dat file to a .tin file.Then dtm tools load and select your new tin file and click on the general contours feature below. Click read at the bottom right of the box to establish minimum and maximum contours bounds and load for view only to check data.