Rendering pyro with volume lights

[bigwil357]

Hello!

I have a Pyro Fire sim with smoke, on a house which is 100 frames. The pryo sim is 100 frames, with a static camera. A volume light is on my fire, and the light from the fire reflects on the house as expected. I also have an environment light for over all lighting.

My questions are;

-How do I render out the fire & the smoke? Should i render them out together (Which i know how to do), or separately. And if separately, then how do i split the two simulations? I also have some of the fire light scattering on the smoke & i have rendered out a fire and smoke mask as well, if that makes any difference.

-The other question is, since my camera is static, i should only need one frame for the house lit by the environment light. Can i render out the volume light pass from the fire separately, so i dont have to render it all with the house? Thanks in advance! 

[StepbyStepVFX]

Hi,

Have a look on the object tab of your Mantra node to "candidate object", "force Matte", "force Phantom", and see how to use that depending on how you want to comp your fire.

Be careful in comping these semi-transparent objects, if you apply different color corrections on them : you can get fringe effects. To avoid that, one of the best way is to render deep images (deep exr for example), and deep comp them in Nuke for example.

https://www.sidefx.com/docs/houdini/nodes/out/ifd.html

Another helpful thing is cryptomatte, again depending on what you want to achieve :

https://www.sidefx.com/docs/houdini/render/cryptomatte.html

Hope this helps you find a way to solve your problem

[bigwil357]

Thank you so much! This helps alot!