.qc (dot qc) - the group for quake c coders of all denominations. If you make quake one mods and write code in quake c, join our group! I'll try to answer any quake c questions - please post your inquiry in the forums...
"N" is trace_plane_normal !
finally...not my sketch, and came with no credits. dur.
The curved surface would be the world brush, or bmodel traceline hit.
"u" and "v" make the traceplane and "N" is its normal.