Diffusion flame experiment in what's to be #EmberGen 1.0

How to: Start with a simple sphere emitter, disable all forces and vorticity confinement, and crank up the temperature diffusion to some really high amount. 2000% in this case is basically doing 24 blur passes atm, but that will be improved.

The shape should stabilize itself due to the high diffusion spreading out the rffect of buoyancy. The diffuse flame shape can already be seen, and it's up to us to extract it from the rest. Next kill any smoke generation, mimicking complete combustion

Next we identify the relevant ranges. The temperature (fire color) is diffuse and spread out, while flame density itself (fire intensity) is sharp since we applied no diffusion to it. We want to sharpen the colors a bit, and carve out a hollow flame "film" from the core

The extinction temperature (cutoff for flames disappearing) is around 2000. The maximum temperature value injected is around 4000. Around 2500 seems like a good isovalue to build the hollow flame around. We isolate the 2000-3000 temperature for shading, to map it to a gradient

Next add some false coloring to the gradient to more easily pinpoint the ideal locations to put our colors

Around the purple region looks good, so place an orange color key there snd some black keys on either side. Black color for the flame makes it invisible, since the flame is fully emissive by design The lower threshold culls the outer part (cold), the upper the inner core (hot)

Slicing through the flame we can see it's actually hollow, and the flame is actually only visible in a thin-ish shell. This is actually very close to how flames actually behave, although we come upon the same *behavior* by different (technically incorrect) means.

And finally we add a bit of low frequency noise masked by the emitter to make it wiggle a bit, emulating natural variation in air movement that almost always exists. Looks quite alright, I think!

On this topic, I can really recommend this absolutely phenomenal lecture series on youtube, a modernish retelling of an iconic lecture by Faraday:

This short video is also actually quite nice and concise:

What is Space Force? Is it Really Real? #spaceforce #nasa #StarTrek