It's quite good on massive field sizes as well, even with only a few veggies. Wouldn't be any good in IM though, since it uses field sizes. It would be really handy if field dimensions could be accessed in sysvars...
It should be possible for a smart bot to determine the field size for fields larger than size 4 by thrusting horizontally a specific amount and measuring the resultant change in xpos...
I could easily add the appropriate fieldsize sysvars, but it would go against the principle of locality. I.e. that bots should only have access to local information and that if they want to know global sim settings, they need to figure them out for themselves. We do have maxvel though although it should not be hard for a bot to determime that for itself as well. Personally I'd like to do away with it. That would leave only xpos, ypos and the asscoiated refvars in violation. I can kind of justify xpos, ypos as a substitute for long-range vision e.g. seeing mountains in the distance, etc. Call it a poor man's way for bots to rendevuez. But I wouldn't miss them if they went away.
The refxpos, refypos and trefvars don't bother me so much since they can only be accessed when close. Said another way, we could make them relative to the viewing/tied bot instead of absolute without any real loss of capability. They onyl violate the principle in that they help the bot figure out it's own absolute position. Angle and dist would still work just fine if we made them relative. Since maxvel can be easily calculated by the bot itself, it's really only xpos and ypos that violate the principle of locality. Do away with them and make the refvars relative and we woudl be clean...