How to render Fire and Smoke as separate passes with V-Ray?

Using the VRayAtmosphere pass you can get the Fire and Smoke together. You could extract just the fire using the VRaySelfIllumination element. After that by subtracting the Fire you can get the smoke.

Check our tutorial here

How to render Z-Depth, Normals, Velocity, Cryptomatte Render Elements with Phoenix?

Use Volumetric Geometry Render mode.

How to use Phoenix as a Matte surface? 

Currently it's not supported.

How to fill an object with liquid? 

Check our tutorial here

My foam/splashes are not displaced with the liquid. 

Make sure that your Particle Shader is using your Simulator as Liquid Simulator.

My foam renders all white in the Z-Depth pass. 

Turn on Render as Geometry in the Particle Shader.

My foam/splash particles are flickering.

Make sure you have a bottom below your particles (V-Ray plane with black material will work for most of the cases), otherwise they will not behave correctly.

Make sure you have enough reflection bounces in the Particle shader options if you are using Bubbles, Cellular or Splash modes.

Can I output my simulation in VDB format? 

In the Output dialog set your output format to .vdb Appending a .vdb extension after the Output Path tells Phoenix to write its data in the OpenVDB format. Particle data can also be exported. 

Can I convert .aur caches to VDB?

The Cache converter command-line utility can convert already existing .aur cache sequences to OpenVDB sequences without simulating.

Is there a way to create a simulation and use the last frame as an initial state? 

Use the Load button. 

How to slow down the simulation that I have?

Check our tutorial here

My smoke has artifacts/noise. 

Try lowering the Light Cache Speedup or turning off Phoenix’s Light cache option - it will slow down rendering but should eliminate the problem.

How can I make my geometry move with the simulation? 

Check our Active Bodies Guide here

What hardware should I get for Phoenix? 

Check our recommendations here 

My smoke/liquid is exploding (not behaving correctly). 

Make sure you are using proper, shelled geometry that has some thickness (no overlapping faces or vertices, no open edges).

How to simulate with Phoenix on different machines?

Check our guide here

Does Phoenix support distributed simulation?

Distributed simulation in which different parts of the same simulation are calculated across several machines is currently not implemented.

Why my renders look strange every 15 frames?

Probably you have Motion Blur enabled in the settings of your renderer, but Phoenix has missing Velocity channel and renders with motion blur only in the Backup frames. Make sure that you have the Velocity channel exported in your Output rollout. You need Grid Velocity for motion blur of volumes or meshes, and Particle Velocity when rendering motion blurred particles with a Particle Shader.

My Fire/Smoke or Liquid has no motion blur.

Make sure that you have the Velocity channel exported in your Output rollout.

My Source is not working correctly with assigned textures.

Make sure you have "Alpha is luminance" turned on from the texture options. If you are using Phoenix without a V-Ray license make sure to turn off Use V-Ray for Texture Sampling. Note that this will make the sampling of textures a lot slower.