How to make waves lap up against static objects, and create foam

[clay_creative]

I'm using the standard ocean setup in Phoenix FD 3.0, and I'm looking to have the water waves hit static objects and create spray/foam etc. Currently it looks as if the waves aren't even really reacting to the static objects:

https://vimeo.com/346905646/ac790b592e

I would also like to see foam around the static object like this:
https://vimeo.com/19414182
https://media.npr.org/assets/img/201...4540.jpg?s=140 0
https://www.telegraph.co.uk/content/...tty-xlarge.jpg

Even if its not 100% physically accurate, I would like to really emphasise this effect of the waves hitting the static objects, and creating foam and spray. What is the best way to achieve this?

Many thanks

Luc

[Svetlin.Nikolov]

Hey,

The waves definitely are not reacting to the scene objects - the Ocean displacement is a render-time effect so it does not affect the simulation. You should use the Phoenix Wave Force if you want to have the simulation interact with obstacles in the scene.

Alternatively, you can use the render-time approach and combine the ocean displacement with a material color coming from the Phoenix Foam texture. It creates a procedural foam map over the ocean waves and you can also use the V-Ray distance texture to multiply the foam tex, so this way you can limit it only near a geometry. This would work if you have distant shots without the need to see up close splash flying and foam bubbles.

Hope this helps, cheers!

[clay_creative]

Ok great. I'm starting to get some good results with that. Though the foam is only generated within the container. So foam can be seen as a square patch on the ocean. Is there a way to 'feather' the production of the foam, or possibly make the shape of the container cylindrical (I doubt this last one). I'm also at a complete loss on how to reduce the size of the large foam bubbles. I've changed the variation small, large and distribution, and I still get massive bubbles

[georgi.zhekov]

Hey,

The foam is generated only in the simulation grid boundaries. If you wish to have foam outside of the grid you can use the Foam texture that Svetlin suggested in his post. You can find more about it here - https://docs.chaosgroup.com/display/...oenixFDFoamTex
You can control where the foam is born using the Birth Volumes - you can find how this works here - https://docs.chaosgroup.com/display/...quidFoam-Birth

Unfortunately the grid can be only a box, there is no way to make it cylindrical.

If those bubbles are indeed foam you can reduce their size from the Particle shader (it controls how the particles will be rendered) - https://docs.chaosgroup.com/display/...er+%7C+PHXFoam .

It could be that those large bubbles are splashes (if you disable the rendering for the foam Particle Shader and the bubbles are still there then these are splashes) which can be reduced in size if you increase your grid resolution.

Cheers,

[clay_creative]

Thank you both, but wow is Phoenix hard and time consuming to use. It's really difficult finding what the problem is with a scene then you have to move the parameters around without any real reference of scale (most numbers don't have units or an upper or lower parameter), and then simulate, and then render, then repeat. its super tricky. Though I do really appreciate you help. I've tried dabbling with the foam shader, and I tried to make the material setup seen here:
https://docs.chaosgroup.com/display/...BlendSetup.png
but I have no clue what the material labelled 'water' is. I tried just using a vraymtrl with just black, thinking it doesn't matter, but it did (ocean rendered black). I wondered if it was a material that was already on the ocean, so I checked in the material editor but all that was applied to it was the ocean map.

What is the 'water' material, and then once I have setup this material do I simply apply it to the 'PhoenixFDLiquid001'?

Many thanks

Luc

[georgi.zhekov]

Hey,

The parameters that are units related already have this reflected in the UI (just make sure that you're not using the Generic units option in the 3dsmax Display units options). Is there something that you think is not properly explained in the docs?

In order to create a water material - set the diffuse color to black, set the reflection and refraction colors to white, set the IOR to 1.33 (this is the index of refraction of the water) and add a little bit of bluish color to your Fog color (this one is quite sensitive so you can play around with the Fog multiplier).

Then if you wish to use only the Water material you assign it to the Liquid simulator . If you wish to use the material with the Foam texture and have the foam crests showing outside of the simulation grid, assign the Blend material to the Liquid simulator just as in the screenshot you have mentioned above.

Cheers,

[Svetlin.Nikolov]

Just updated the docs on the Foam Texture since they were untouched for a long time and were not clear. If you find any issues in the docs or something does not make sense, please ping us and we gotta fix it

[clay_creative]

Hi All,

I'm still having a few problems with this scene and it would be great to have your input:

https://vimeo.com/346905646/ac790b592e

1. I tried adding the foam texture as instructed (see attached image), but no foam ever gets added, so I'm not sure what i'm doing wrong here?

2. I tried to identify if the bubbles are foam or splashes by turning them on or off but they still show with both foam and splashes disabled, do I have to re-simulate with one of them off to determine which it is? I would think that turning them off after the simulation has been completed would turn them off?

3. The waves generally didn't react with the geometry even with the liquid simulator so I thought I would go a bit 'hacky' and animate the geometry wiggling around a little, I was thinking that I could then simply set the placeholder geometry to not render and add in the final geometry once the simulation has been completed. However things go really crazy, really quickly. It almost seems like the whole liquid square turns into a bubble bath. I'm not really sure why the water affected by the animated geometry isn't more local, and its not as if the animated water is rippling out to cause the chaos. You can see in the animation that almost instantly the whole square becomes really animated rather than just the bits around the geometry. I would think at this scale the water would quickly loose its energy.

4. If the bubbles are indeed 'splashes' I've done as instructed and increased the resolution, but this in turn makes the simulation even slower, and it hasn't decreased the bubble size. Why are they set so massive by default, and why do I have to increase the resolution of the grid (which also makes the simulation take longer) to make them smaller, surely there should just be a parameter to make them smaller?

5. When working on the scene my workflow thus far has been: Change a parameter, simulate 100 frames overnight, render the scene over the next night, then review the following morning. This means that every parameter change takes 2 days to evaluate. As a newby to Phoenix, and there being about a billion parameters with different scales, this process is going to take me years to get the scene to a good place. Is this how people generally work, or am I missing something?

6. Can I combine different ocean maps to make the ocean less consistent. I think it looks more realistic to see patches of different currents (I assume that is what causes it), like in the distance on this image. You can see patches of water that look lighter/darker in the distance:
https://www.shell.us/energy-and-inno...portfolio.jpeg

Sorry to have so many points in one post, but I thought I would put it all down so you could see if my approach was all wrong.

Thank you in advance

[georgi.zhekov]

Hey,

1. For the Foam Texture -try to set your tilling to 1 for the Ocean Texture and adjust your scale by turning on the Control by Wind Speed and changing the value. Looks like there is an issue how we treat the mapping for the Foam when the ocean has small tiling values.
In order to dial in the correct values for the Control by Wind Speed without simming - you can turn on the Pure Ocean mode in the rendering rollout of the Phoenix Simulator. You can find out how this works here - https://docs.chaosgroup.com/display/...endering-Ocean
Just make sure to turn it off, when you're done.

2. The Foam and Splashes are simulated by the Phoenix FD Simulator but are rendered by the Particle Shader. So in order to disable them from rendering you will need to select the appropriate Particle Shader and set it to be non-renderable.
When you disable the Foam or Splashes from the Simulator - you disable them from the simulation only and not from rendering.

3. The interaction with the geometry depends on your grid resolution. The higher the resolution, the better your interaction with the geo will be but this comes at the expense of simulation time. So you will need to balance this out.
In your case you have a lot of bubbles, because your Birth threshold for the Foam/Splashes is really low and when the geometry is moving it creates foam/splashes. In order to have less bubbles you can increase your birth thresholds.

4. You can control the bubbles size with the Particle Shader. You can find more about the Foam and Splashes and how they work here- https://docs.chaosgroup.com/pages/vi...oamandSplashes

5. Depending on your shots - you can work with lower resolution grid and less particles at the start so you can get the general feel for your simulation and increase those values when you have something that you like.

6. In this case you can use the Displacement scaling option in the Ocean Texture. Just plug a Noise texture as an input for it and you can get quite good variation in your displacement values.

Cheers,