"Standing in a cloud of colored dye," and this wouldn't be awesome?
No, but seriously, for the sake of functionality, what if we dropped the idea of rendering ambient temperature gradients and just went with the block temperature of the reactor core(s), boilers, etc. then? It would maybe be a little uglier but at least we'd have an overview of where our hotspots are and whether or not they need to be addressed (Blue == I need more heat, Yellow == OK, cooking away, Red==Oh shit! and gradients in between).
On that note, just out of curiosity, why don't hot objects radiate heat energy into their surroundings and make changes to ambient temperatures? Emergent behavior or potential for abuse? (I can't imagine that it would be very pleasant standing next to a hot reactor
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