to add physical walls to a .trk file you must edit 4 parts of the file. Using N3def from BB&B, open the trk file, in converted txt format, in notepad. For every wall you add, you must add 5 to section 3 of the header. this will tell the track about the 5 new numbers you are adding to the file. Then, go down to the pointers. Each pointer corresponds to a track section. Find the section that has the new wall. take it's number and add 112 to it and that becomes the number for the next pointer. after that, all sections with 2 walls will increase by 92 and all sections with 3 walls will increase by 112. (4 walls would probably be 132, not sure) Next, scroll down to the section where you are adding the wall. In the section data line, scroll out to the end where it says Walls. Under it is a the number of walls in the section. Change that to match the new number. Then scroll down to the walls section. Take one of the walls and copy and paste it right underneath. The wall type needs to be 4 (I think) Change the next 2 numbers to wherever you want the wall. These numbers are in relation to distance perpendicular to the centerline. The last 2 numbers are fine as is.