The "OFF" header tells us it's a polylist file. The second line in the file tells us that there are 20 vertices, 12 faces, and 30 edges. The next 20 lines give a list of vertices. The last 12 lines specify the faces: the first number is the number of vertices in that face. Since our polyhedron happens to be regular, all faces have the same number of vertices (in this case, 5). The rest of the numbers on the line are indices into the above list of vertices. Besides being compact, the polylist file format embeds connectivity information in the Geom.
OFF 20 12 30 1.214124 0.000000 1.589309 0.375185 1.154701 1.589309 -0.982247 0.713644 1.589309 -0.982247 -0.713644 1.589309 0.375185 -1.154701 1.589309 1.964494 0.000000 0.375185 0.607062 1.868345 0.375185 -1.589309 1.154701 0.375185 -1.589309 -1.154701 0.375185 0.607062 -1.868345 0.375185 1.589309 1.154701 -0.375185 -0.607062 1.868345 -0.375185 -1.964494 0.000000 -0.375185 -0.607062 -1.868345 -0.375185 1.589309 -1.154701 -0.375185 0.982247 0.713644 -1.589309 -0.375185 1.154701 -1.589309 -1.214124 0.000000 -1.589309 -0.375185 -1.154701 -1.589309 0.982247 -0.713644 -1.589309 5 0 1 2 3 4 5 0 5 10 6 1 5 1 6 11 7 2 5 2 7 12 8 3 5 3 8 13 9 4 5 4 9 14 5 0 5 15 10 5 14 19 5 16 11 6 10 15 5 17 12 7 11 16 5 18 13 8 12 17 5 19 14 9 13 18 5 19 18 17 16 15
I use Geomview program to view OFF files.
