Hi guys.

Looks like the question never has been asked. I'm a kind of new in da “Houd” and i'm totally amazed by possibilities. I have a decent bunch of experience years using Maya and i can't believe how big the difference is.

That's said, my question is, please, how can i get a decent whitewater foam look?
By default, the material applied is the default spray shader but gives me that smoke look. (joined screenshot) and even reducing voxel size doesn't help me.

The documentation looks poor about that but maybe it's so obvious that it doesn't need more explanation?

For me the best references right now still are

by Graham Matthew Collier

https://vimeo.com/72879742 [vimeo.com]


And of course by Master Igor Zanic

https://vimeo.com/65490463 [vimeo.com]

I think the best solution to get near these looks is to render whitewater as particles instead of volume smoke. May i desperatly wish for some help around here?

I found it! By changing the shader to billowy smoke, reducing the voxel size, and the last secret information that i couldn't find anywere, is to reduce pointwrangle= @pscale and tweak from there.

Now i'll need to find how to render only the top of the flip simulation. I'm hugely open for informations guyz!

yep… thats a definite improvement

After you mesh the water, why dont you group by bounding box then delete the group? Ive dont that before and it works well.

A: Thanks a lot Jordan! that's helping me a lot. I tried to group by bounding box and add a delete node, it works good but if i have too much wave height some parts are going outside the bounding box and create holes. Maybe there is another way?

B: I have done a very basic simulation in order to test compositing. I'm very far from the whitewater i'm looking for but it's just for the test sake.
I'm having an issue, looks like whitewater underwater are included in the alpha and create these black shapes. i think i need to tweak more with the render settings.. (see attachement picture)

C: Video Link:

https://vimeo.com/77433626 [vimeo.com]

This is a more complex sequence test. The Collision object's animation is far from perfect i'll modify it for sure. The splash doesn't quite look cool at this point snif. Maybe you guyz are combining rise animation with force fields? I really need a more spectacular rise splash. I don't understand why i have those flat waves at the biggest velocity level, from my general experience it sounds like a substeps issue…??

Is it possible to create the whitewater(shelf) with a cached Particle_fluid instead of a FlipTank object?

Ok looks like i'll keep finding solutions right after posting here and asking for help. Actually i think thoses flat shapes are particles blocked by the flip tank roof…. Arghhh! re-sim again… I'm still open for advices and tips!

Group your points by expression ($TY > 2.5 for example) instead of bounding box , maybe this will work

Also you can group them by velocity expression ( ($VX + $VY + $VZ ) > 10 for example )

Hi
I'd consider using a particle render with a shader that has specular reflection and diffuse, after-all white water is tiny drops of water, I find that spec reflection helps give it a more natural look. I used a similar set-up with this: https://vimeo.com/33588272 [vimeo.com]

jason

Insane Jason! very very good shot!

Actualy, I'm stuck with a black screen when i render the cached particle bgeo whitewater(from the wave tank). I switched the “import_whitewater” node to “render only point” but nothing happens…??? am i missing something?


Looks pretty simple Joker, i'll investigate! Thanks a lot!

it should render, do you have a pscale attribute on your points at all?

jason|slab
Hi
I'd consider using a particle render with a shader that has specular reflection and diffuse, after-all white water is tiny drops of water, I find that spec reflection helps give it a more natural look. I used a similar set-up with this: https://vimeo.com/33588272 [vimeo.com]

jason

That looks great Jason! Any tip on how to add normals to the whitewater particles?

you can as well just render it as points with Lighting Model set as Isotropic Volume to get volumetric look that's cheap to render even with millions of points
no normals necessary

Skybar
That looks great Jason! Any tip on how to add normals to the whitewater particles?

A good trick here is to use polygon to vdb to convert your point cloud to a sparse volume.
In vex vops you can then use the point positions of your original point cloud to sample the gradient of this volume and obtain faux-normals.

tamte
you can as well just render it as points with Lighting Model set as Isotropic Volume to get volumetric look that's cheap to render even with millions of points
no normals necessary

Oh that is neat, didnt know about that. I do need the whitewater to reflect right now though, but I'm sure I will use it in the future. Cheers!

glassman3d
A good trick here is to use polygon to vdb to convert your point cloud to a sparse volume.
In vex vops you can then use the point positions of your original point cloud to sample the gradient of this volume and obtain faux-normals.

I couldn't figure out how to do that, so I went one step further and meshed the whole thing instead - and then AttribTransfer the normals from the mesh to the particles. It works quite good, except the meshing isn't that quick because of the sheer number of particles. I don't know how much faster that gradient stuff is, you would still have to use VDB From Particles which is what is taking it's time anyway. It creates the look I was after though, so I'm happy. Thanks!

I have tried rendering particles created using the Whitewater shelf tool as points as well and I am also not seeing any points rendered.

The points do have a pscale set

Hi,

I am completely new to Houdini and with help have managed to get to adding whitewater to my waterfall, but now i've got black bits in it and I can't figure out why?

Any help much appreciated!!

Thanks