how to create a guided sim ocean wake

[JasonA2071]

Ive been working on a ship/ocean scene and Ive started with the "ship on the ocean" tutorial which is a great get started point. Ive tweaked settings to get a more desirable effect, but Im never getting results that are like the bifrost boss demo from 2017. It seems that the process in the phoenix tutorial, it doesn't use a 'guided simulation' approach to create splashes and foam based on the ocean's waves interacting with the hull. The ambient waves seem to have no interaction with the hull. When comparing the basic steps that autodesks demo shows, it seems the phoenixfd process omits the part where the ocean appears to be simulated a second time for the ocean/wave/hull interaction. My results, like the tutorial, only generate splashes and foam based on the waves/wake that the ship itself creates. Thus there are no secondary waves/splashes.

The difference in the results in very noticeable. The boss bifrost demo Im referring to is this clip on youtube: https://youtu.be/xcoiugB6WwY?t=25

Its it possible to do the same process that the bifrost boss system uses with PhoenixFD?

[Svetlin.Nikolov]

Yes, indeed, the ocean is a render time displacement. If you want a real simulated ocean, check the Wave Force node.

Cheers!

[JasonA2071]

Thanks Svetlin, I found the node, and I see how it works with the simulation volume. How does this integrate with the infinite ocean? I see that if I change the Render Mode to ocean mesh, the infinite ocean appears but has no displacement. I was about to add the displacement texture to it, but wont this cause a 'double' displacement inside the volume grid? It appears to cause a displacement everywhere and I havent run the sim with the wave force yet.

Do I need to make two separate scenes, ie1 infinite ocean with texture displacement, and 2. render of just the ship and the volume grid, then composite together? If this is the case, how do I get only the top surface of the simulation grid and not the sides? the "Cap Mesh" mesh type seems to be what Im after, but the edges are rounded...

Or am I thinking about this all wrong, and theres a way to get both to play nice together in the same sim?

[Svetlin.Nikolov]

Yes indeed, there is no automatic way to blend a simulator with a wave force and the infinite ocean. Displacement will get doubled inside the simulator, so maybe you could use the Fade Volume option and add a non-solid, non-renderable box the size of the Simulator to suppress the displacement inside it. Unfortunately for now you have to workaround it

[Ivaylo Katev]

but wont this cause a 'double' displacement inside the volume grid?

In general the displacement tries to not displace the water that is naturally displaced by the simulation (see the Vertical Fade Level parameter) .
Of course this simple mechanism is not entirely preventing the double displacement, but on the other hand the result from the force is not an exact copy of the ocean texture, at least the fine wave details are not present. Playing with the force multiplier, you can achieve good matching between the ocean extension and the simulator content https://vimeo.com/143147392

[Svetlin.Nikolov]

Yup, the Fade Above Velocity option should also work. In general, there are 3 ways you could suppress displacement, and you can combine them - you can find out more here: https://docs.chaosgroup.com/display/...g-Displacement

[JasonA2071]

Thanks guys, Ill give these suggestions a try. Much appreciated!