How To split Elements (Render passes)

[Vincit]

Hello guys,

I have been testing Phoenix for couple of weeks and i have a few questions:

1 -I noticed render times come to a halt when rendering foam+Splashes (bubble + splash mode) and Liquid mesh with vray Refraction liquid material on it, As soon as the Refraction material is applied on the mesh the render takes ages, is there something wrong i'm doing here? i am using vray 3 in max 2014.

2 - naturally this leads me to think of multiple passes for compositing, after the simulation I want to render the splashes and Foam separately from the mesh, I can't find a way to have control over the individual elements, where can i disable the foam/splash vs the liquid during rendertime or hide them and then render them out separately.

3 - one last thing keeping the above in mind, I would like to render the main liquid body mesh +the reflection pass of the foam and splashes, and then render out the foam+splashes without the liquid body mesh, its important to have the subtle reflections/shadow pass of the foam onto the liquid rendered together or as a pass to help with proper compositing.

your help is much appreciated!

Thank you

[Ivaylo Katev]

you can disable the foam by the "renderable" object property, the same for the mesh.
if you need z pass for the foam, ask for nightly build access, because we fixed one bug related to it the last week. and render it in geometry mode, the atmosphere objects can't produce z depth.

[Vincit]

Thanks, got it, that worked, I managed to select the foam and disable "cast shadows" that helped speed things up by some 400% for the renders, and there was no significant visual difference form the intial tests so far.

I don't want to derail off the subject of this thread, however I am trying to simulate breaking waves from a large body of sea onto land, but i need this to be detailed for there are ships and people swimming near the shore and each particle should interact with those people on medium shots.

I'm looking to achieve something like this: http://www.youtube.com/watch?v=H-uxjZs48y4

my questions are:

1 - I noticed there are no forces or Daemons (like the ones in realflow) which would help you get that movement of the sea near the shore with the water retracting and then hitting back the shores again, whats the best way to get that motion out there as close as possible with phoenix.

2 - Do you have such forces in the wishlist and are you working on them to release anytime soon?

3 - is it somehow possible to create "higher resolution" multiple small grids within the main grid for a specific portion, say the main body of the water is there, however there are numerous small ships or people swimming near the shore while the camera is traveling close to them and you would want the waves and splashes to crash onto the 2 meter tall person in detail as well as the 30 meter long ships vs the main water body, since obviously simulating such a dense large water body mesh of thousands of meters all over would be very slow.

4 - finally if i wnat to apply a custom material to the liquid surface, how can i map a procedural texture onto the mesh, at the moment it doesn't seem to ahve any normal uv coordinates, for instance if you try something simple say applying a checker map onto the surface of a simulated liquid it wont display or render anything somehow the uv coordinates are missing? i read something about the phoenix texture map but i couldn't understand its purpose fully or the trouble with the "circular reference" error.

Many thanks for your time and support, hope to hear form you again shortly!

[Ivaylo Katev]

1. you can use the max forces, they affect the water, however i would recommend you to avoid them because they are slow. better use animated underwater source, or just moving geometry to push the water.
2. i hope in the next version we will have directly wave generator tool. btw you can use our mapper+ocean texture to initiate waves, i have tried this and it worked. it's described in the forum but cant find it now.
3. i really doubt that it will work. digging into vimeo/youtube , i see that simulating even small piece of shore is really a hard task.
4. we had uv mapping but it is useless, the fluid movement scrambles the uv coordinates and nothing meaningful can be visualized with them. look at this tool it can help you. the idea is to attach a texture pieces to particles and to move the particles with the liquid

[Vincit]

Thanks for the quick feedback, I will have a look at the mapper approach as well as the animated geometry which we have been trying with little success so far, There is something else I am not sure if its a parameter issue or dynamics related, It has to do with the liquid "sticking" to surfaces more than usual when it comes to larger sim areas such as a 30+ meters as well as the liquid dynamics splashing too much upwards I guess i can post some stills soon to explain better.

Thanks again.