uv for liquids.

[jstrob]

Hi, is it possible to have uvs on liquid in phoenix FD. I just boght it and I am playing with the chocolate example. I would liek to add a small bump to the choccolate using a noise map.

[Ivaylo Katev]

in the official version the uv mapping is still supported but we decided that this technique is a wrong way and in the next release will be not present.
why the uv mapping is useless? for short videos it works pretty well, the uv space is still continuous and produces deformed version of the initial image. however after one second the uv space becomes very deformed and the texturing looks like strings.
even in the very firs versions of phoenix we have an alternative mapping method, that is also not perfect but can be used. i speak about particle texture and a technique that is based on it. what is the idea - instead uv space the fluid drags particles. the particle in the final image the fluid near to given particle will be mapped with texture that is based on the local particle space and will move with it.
see the attached sample that illustrates how it looks. you see the central zones are not clear mapped, because multiple particles overlap their influence.
this tool is supported but is not used, i think we can develop it. it was introduced to drive smoke displacements, but the smoke displacement is a bad idea, and so we left the texture mapping in oblivion.
however, i think it may be useful, but not in this form. i will try to improve it

[Ivaylo Katev]

well, i have improved it as i promised, here is a sample of the mapping now.
if you find it useful, i will send you the scene

[jstrob]

oh yes that's cool! I want to know hoe to do this. Please send me the scene.

[Ivaylo Katev]

the scene, you will need latest nightly too.

[jstrob]

great! thank you!

[Ivaylo Katev]

the nightlies are broken, you have to wait before use this

[jstrob]

ok please tell me when it's repaired.

[Ivaylo Katev]

it's fixed now

[jstrob]

great thanks!

[jstrob]

I started looking at that scene. Could you explain abit the setup. there are 3 phoenix object in liquid mode. Do I have to simulate all of them in a scecific order?

[tsetso]

Hi,
you only need to simulate the first simulator (PhoenixFD01). This one is just used for simulating the liquid.
The other two objects you need for now are the emitter (Box001) and the liquid source (PHXSource001). Note that the
source emits particles as well (you will need them later for the ParticleTexture).

Once you have simulated the liquid, copy the simulator (the new one appears as PhoenixFD02).
You will use this one for the displacement. To do that load the cache files from the first simulator, by going to the "Input" rollout of the new simulator and after "$(simoutput)" just type the name of the first simulator (should look like this "$(simoutput) phoenixfd01"). If you hide the first simulator and scrub the timeline you'll see now that the second simulator plays the same simulation.

At this point you're ready to apply the displacement. To do that add VRayDisplacement modifier on top of the second simulator. For Texmap, we'll use the particle texture (PhoenixFDParticleTexture).
Under "Source particle systems", pick the particle group from the first simulator (PhoenixFD01) - OK.
Add some texture to the Map slot of the particle texture (cellular for example) and plug it to the Texmap slot of the VRayDisplacement modifier. That's it!
Just hit Render and you'll see the result.

[jstrob]

Cool thanks for the explanation!

[tsetso]

You're welcome!

[ttdww]

Hi, Please forgive my lack of understanding however, how did you create the PG 'particle group' object in the test scene 'particletexture.zip (33.3 KB)'. I'm rebuilding this scene from scratch and can't figure out how to recreate it. Thanks.