A couple of basic particle Qs

[Joelaff]

Hi,

I haven't done a ton with regular particles in Phoenix, and I am trying to familiarize myself with the workflow. I've done smoke and fire, and water, and splash and foam. I get that stuff.

Now I need to do some fluid type particles that would render more conventionally, either as billboards/sprites, or as points with Krakatoa. I am getting good results with a Phoenix source that is emitting temperature and particles. I only want the particles; so I can hide the PHx simulator to not render the fire.

What is the easiest way to render the particles? If possible I would like to avoid single threaded pFlow, but I could go that route if I have to. What other options are there to render "drag" particles?

The docs say something about a right-click option to export a PRT. I cannot find where this is. Which version of Phoenix did this get added? Perhaps I need to grab the latest nightly.

Thanks.

[Svetlin.Nikolov]

Hey,

With Phoenix 2.2 you can right-click the simulator and export particles to PRT - you just have to make sure you are on a frame where the particles are actually loaded (this will be fixed in the next version).

Otherwise, Phoenix's way to render its own or other particles is to use the PHXFoam shader - it's a legacy name for the object, but it actually is a general-purpose particle shader - it can render bubbles, refractive spheres, points and can also voxelize the particles into fog and use the smoke shader to render them.

Cheers!

[joconnell]

In your simulator, you've got all the various options to export channels. You also have a section for exporting particles at the same time and what data you'd like for those particles. Knock that on and do your sim. When it's done, go to a frame of the sim where there's data and then right click on the phx simulator and choose export particles - you've got to set your start and end frame manually but should get the option of whatever particles you've chosen to sim.

[Joelaff]

Thanks, guys. I was stupidly looking for some kind of right-click option in the rollouts of the command panel... Duh! It's in the quad menus. I might add that note to the docs (right-click in the viewport). Or maybe I haven't had enough coffee yet.

I have used PHX Foam. It is quite versatile, and very fast for what it does. That is definitely one option.

Any ideas on sprites? I think I might have to do those in pFlow, either loading a PRT, or using the PhoenixFD Force? I know how to use those. Just curious if there is some better way to do sprites/billboards.

Thanks.

[Joelaff]

OK. How can I get a matte of a PHX Foam element? I tried geometry mode, and putting the PHX Foam in a MultiMatte Element. This didn't seem to work.

Thoughts?

Thanks.

[Svetlin.Nikolov]

Hey,

It should work even without geometry mode with a simple VRay Matte Shadow - the MultiMatte is broken though and we have it in the TODO list.

Also, if you are running the official Phoenix currently, you should also make sure to drop a mail to support and get access to the latest nightly builds - there are tons of improvements and fixes since 2.2 came out.

On the sprites - Phoenix Force and PFlow's Shape Facing Operator should to the trick.

Cheers!

[joconnell]

this is a shot in the dark but could you get a matte from the foams material using multimatte in matID mode instead?

[Joelaff]

I am specifically trying to get a matte of the foam itself.

Joconnell: I could not get MultiMatte to work with MatID. I can't find any place to set the MatID of a PHXFoam.

I ended up using a MultiMatte and adding everything else, except the foam. This gave me an inverted matte.

Note I am using ONLY the particles with PHXFoam. I have the PhoenixFD hidden and am not using smoke/temperature at all.

[Joelaff]

What this did not solve, though, was that I was hoping to get one matte for each of three different PHXFoam particle groups. In a single PhoenixFD I have three PHXSources. Each of those has its own PHXFoam in order to get a different look for each one (this effect is bright colorful particles, more like pixie dust than something realistic).

[joconnell]

The matid would go onto the material assigned to it so you'd be choosing it in the material editor. Another option that sometimes works is an extratex element with a vray color map in it and using the include / exclude list to choose only the objects you want a matte for.

[Joelaff]

The matid would go onto the material assigned to it so you'd be choosing it in the material editor. Another option that sometimes works is an extratex element with a vray color map in it and using the include / exclude list to choose only the objects you want a matte for.

You can assign a material to the PHXFoam? I thought you just used the color in the PHXFoam itself. To which object do you apply the material? (I am familiar with material IDs, but not how to get a material assigned to the PHXFoam output.)

[Joelaff]

Interesting idea on the VRayExtraTex. I am not able to get it to work, though.

I added a VRayExtraTex element. I set the texture to a VRayColor map set to Red. I then set the PHXFoam object to be included (everything else excluded). The element renders black

[Joelaff]

Oooohhh!

I got the VRayExtraTex to work! I had Geometry mode turned off in the PHXFoam. With geometry mode on The VRayExtraTex method works. That is pretty slick! Thanks!

[Joelaff]

So I tried to expand on this and get something like an RGB Multimatte. I tried using a VRayUserColor as the texture for the VRayExtraTex (with PHXFoam applied to a PRTLoader, and Geometry mode ON-- each PHXFoam has its own diffuse_color defined in the user vars). This was to let me get three different colors for the three different PHXFoams I have. However, this setup makes VRay (and Max) crash!

[joconnell]

Geometry mode should work with normal multimatte now too!