Multicolor scene file

[etown]

Could one of the wonderful Phoenix developers post the multicolor scene I've read about? It did not install this in my documents folder and I can't figure out how to render multiple smoke colors.

Thanks!

[Ivaylo Katev]

there are two sample files with colored smoke, the old one is actually colored fire (four colors), the new one is particle based.

[etown]

Do you recommend using particles with 2.1? I only have two objects that I want to emit smoke. They are moving around each other and I want each object to have its own smoke color. What's the most simple way to achieve this or is there a video tutorial available that walks you through this? The sample files are proving hard to understand the step by step solution.

[Ivaylo Katev]

yes i recommend to use particles, just modify the water in ink sample scene, it does exactly what you need.
and don't remember to prepare 1TB HDD for the cache files the sample file eats about 400G, and has 4 objects, but when you modify the scene it may need bigger disc space
and short instructions how to modify the sample scene:
- create and animate your bodies
- delete the original bodies (cylinders on the top of the container)
- select the source helper (the barrel)
- there is a list named "target objects", select your bodies in it
- decrease the particles parameter. in the original scene it is 500 000, make it 500, this means 500k particles per second.
- select the simulator
- open the grid panel and decrease the grid resolution down to 500k, this is just to simulate faster during the setup, you will increase it back for the production
- start the simulation
- in the original scene you have four PHXFoam shaders, these umbrella-like objects. delete two of them, two must remain.
- there is a particles system slot in the PHXFoam object, it placed in the top of the panel. push it and pick the simulator. a subnode dialog must appear
- in the subnode dialog you must see two objects, each of them representing the smoke of the corresponding body, select them each in separate PHXFoam object
- adjust the color, make a test rendering
- iteratively increase the particle birth rate (in the source helper) and simulate until the single particle is not visible but continuous smoke is visible in the render. during this process you will get denser and denser smoke, you can adjust the density using the ior parameter of the PHXFoam object. each simulation will be longer, but you can simulate only the first frames just to see how it looks.
- when everything is ok, increase back the grid resolution up to 8M or even more, 50M would be good. the bigger grid resolution will not affect the smoke density, but will add small details that make the smoke to look better.

edit: if you need disappearing smoke, you have to animate the size multiplier in the PHXFoam object to change from 1 to 0, and to enable the PA option, it means particle age. this will decrease the particle size when the particle becomes older.
unfortunately there is no option to kill simple particles during the simulation, we have to add it.

[etown]

Thanks for the detailed instructions Ivaylo. I'll give it a try shortly.