[Mobhack]

And fire hexes can be seen through as well, but unlike SP2/3 thermal vision is not unlimited through fire hexes, there is now a cumulative degradation and so enough fire hexes will eventually stop the LOS of thermals.

And larger fires will contribute more blocking factor, any smaller fire hexes less. So having fires dotted about the place, whether burning trees, wrecks and buildings or say a Buratino salvo of flame rockets going off, will tend to produce some thermal "shadow zones" when trying to spot through it with TI.

I cannot recall when we added that, It may have been back in the MS-DOS days, but its there now.