Realistic fire

[FoXar]

Hey guys,

The title says it all, I've been searching on the forums and I found some interesting things.
But none of them were really spot on.. Especially for use during daylight, I'll also post some renders
when I get the time to play with it

[lycium]

For this we'd have to implement emissive participating media, which has been under consideration for some time and is tricky to sample efficiently etc... but I'm sure Nick has some tricks up his sleeve for getting this going

[FoXar]

Hey guys! Tricky sure it is..

Been testing severall things, always this same result.

I use a texture and a clip map, wether it's a transparent png or a clip map, always the same result:

Didn't bother rendering for longer, as you can easily see what the problem is.. Also for some weird reason my sky isn't working anymore since I made that material.. :/

[CTZn]

Uncheck "Step Blend" in the SkIndigo blend material editor if you are not using a clip map. Step blend will always cause clipping. It is good to use it with clip maps as well since it does remove their aliasing.

Next thing is to lower the fire emission gain, it is currently tenths or hundreds of times stronger than the sky itself, if not more than that. Use the Camera default tonemapping to get an idea of that strength.

Normally a blackbody emission spectrum would be used with a temperature around 3000°K... you could also use the emission map as displacement to give the fire plane some circonvolutions.

Volumetric emission yay.

[suvakas]

I made fire once.
http://www.indigorenderer.com/forum/vie ... f=4&t=5801

Those are emitters with alpha maps.
You just need to have good photos of fire. And yes, don't use step blend.

Suv

[harrybro]

ok thanks mr suv...

[FoXar]

Hey CZTn,

Thanks for the reply, I understand and I'll make sure to look at it, currently I have done my efforts through photoshop as I didn't find the time to play with it, should be doable this week though!

About the gain, I have an error somewhere in the scene, I think I have an exit portal assigned to a face I don't know about, because if I add exit portals I have light though.

@suvakas, great! Thanks for your reply, that looks pretty awesome!

[Zom-B]

Hey Foxar,

I did some Fire in my last project: http://www.indigorenderer.com/forum/vie ... =4&t=11946

its a simple 2D setup as you see in the image attached, but the emitter material was set to be doublesided in the igs via:

Code: Select all

<backface_emit>true</backface_emit>

[CTZn]

the emitter material was set to be doublesided in the igs via:

Code: Select all

<backface_emit>true</backface_emit>

Never heard about that one, could we please know more ? I'm sure there are a couple more things I missed.

Suv's fireplace is great !

Also FoXar from several references it is common for the flames to look flat and yellow in LDR.

[Zom-B]

the emitter material was set to be doublesided in the igs via:

Code: Select all

<backface_emit>true</backface_emit>

Never heard about that one, could we please know more ? I'm sure there are a couple more things I missed.

You use it like that:

Code: Select all

<material>
    <diffuse>
        ....
          <backface_emit>true</backface_emit>
    </diffuse>
</material>

plane single sided emitters emit in both normal directions with that command, great for some fake torch fires etc.
Its an addition to Indigo that was somehow forgotten, after I asked for a such feature for the dragon scene, I get the info that its already in.
I'm also allowed to speak about it, so I do

[CTZn]

Got it, thanks Arthur.

[Pibuz]

EHI EHI EHI!
That really sounds like a feature which HAS to be included into SkIndigo!

GOGOGO hidden features!!!!!


.....whhaaaa-aaaaaaat?