fire sim in 1.2 - cell size affects emitted light?

[Tony_Morev]

subj pretty much ...

no additional lights used, just whatever the flames generate by default
going with smaller cell size to gain more detail in the flames also makes the fire emit more light into the scene

if this is normal behavior than it's pretty darn annoying
makes it hard to use low res grid for testing
and with GI influence multiplier nowhere to be found also makes it hard to get the desired look

Ivaylo, is it a bug or a feature?
i'm having a hard time telling them apart lately

[Ivaylo Katev]

sounds like a bug, you mean the lighting is produced by GI and it depends on the cell size? what about the visible fire brightness? is it also increased?

[Tony_Morev]

yes the fire changes in both brightness and size
smaller cell produce taller and hotter fire
substantial enough to where the temperature had to be dropped from 3000 to 1800 to get the same rendered height
but the GI still remained brighter than lowres sim even at lower temperature

it wasn't me playing with, but i was involved in tweaking
unfortunately the guy who worked on it didn't save any image references

[Ivaylo Katev]

well, it's odd that the brightness is changed, it depends on the temperature that is specified by the source. the change of the fire height is different, it's not desired effect but is unavoidable, actually the sim always changes when the resolution is changed. i'm considering an idea about this but is still an idea...

[Tony_Morev]

well, i hope it's a good idea!

right now if i am to sum up my impression of Phoenix in one word that word would be "unpredictable"

and the reason for that is because there is no way to run a low res sim for testing
be it water or fire as it turns out

most of the time real production deadlines require a way to predict the final behavior based on quick tests
and it's just not the case right now with Phoenix, for me anyways

may be someone out there who is having a better luck can share some tricks?
but ultimately i think it's up the programmers to make it more tamed

[Paul Oblomov]

I think phx going toward some advanced ways of simulating. Unfortunately, I guess not before version 2.0 sp1

[Tony_Morev]

well, i really like the interactivity, how anything could be changed while the sim is running
it certainly helps to get the "right look"
but to get guaranteed results it needs to be done at final grid size
and that's what makes it time consuming