Ship in Ocean using Quick Settings (novice questions).

[JezUK]

I'm late to the PhoenixFD party, but I'm trying to get a Ship (obviously drawn to scale) going at 12m/s through an ocean to look realistic with bow waves and foam, splash etc.

We had a previous PhoenixFD solution created for us via a freelancer using an older version of the software and which followed pretty well the Tutorial Example given by the ChaosGroup on YouTube.

However, I myself now have the most current version of Phoenix, but this version I have looks quite different to the version of PhoenixFD used in the YouTube Ship Tutorial, so much so that it is not possible to follow that tutorial any longer.......

So, I find myself looking at my version and the Quick Simulation Settings, and of course I have chosen the Ocean one as my starting point.....

However, it sets things up differently to the said YouTube Tutorial and there isn't enough material around online for me to figure out basic settings for my simple Ocean Scene using the latest version of PhFD.

For example, I've just hit "Start" once I've used the Ocean Quick Settings, and I don't see any Foam, no splashes etc etc as my ship goes through the Ocean.

Am I missing something here ? Obviously there are a myriad of settings to choose from, and play with, but I'm asking myself, why would I need to play with any of those when all I want to do is have a ship go through an Ocean !

So, dumb question number one..... what exactly is the Ocean Quick Start Settings, actually for ? Would I need to change any settings ? (why and which ones).

Question Number 2 - in the older method I've seen on YouTube, the Container is made to be somewhat larger than the ship and is linked to the ship too. In the Quick Settings, the Container is made very large by default. Should I reduce its size and link it to the ship as well ? Or do I leave that large container as it was set up by the Quick Settings ?

Any help would be *really* appreciated.

Many thanks.

[Svetlin.Nikolov]

Oh, so the couple of most important notes would be to first check the Ship example scene on the docs site - it's available for Max and Maya and is the upgraded version of the 2.2 tutorial video, which would not produce the same result with 3.0 anymore.

Also, it's very important to know that the quick setups adjust their scene scale option so that the object (or group of objects) you apply them onto would behave as if they were of a certain size. For example, if you create a fuel fire preset over an object, it would always adjust the scene scale in the grid rollout so that the simulator would be a couple of meters high when simulating. The Ocean preset adjust the simulator so that it would be 125x125x40 meters big, as if the geometry was the size of a ship. This automatic adjustment happens so that no matter if your object was 1 unit or 1000 units, the presets would produce the same result, otherwise they would be impossible to control. This means that if you create a preset over an object that you already know is real-world size, you need to go back to the Grid rollout and reset the scene scale to 1. Alternatively, if you do any resizing of the container after you've created the preset, you need to again go to the Grid rollout and make sure the dimensions in the Total Cells field are plausible in the real world, otherwise you should adjust the scene scale option to correct them.

I hope this helps shed some light Cheers!

[JezUK]

Hi Svetlin,

And thank you so much for your help - I've downloaded the Ship scene you mention and can see that it is indeed using the upgraded version of FD. Please may I suggest that a note in the 'old' Ship Tutorial mentioning that this is the case, is added so that people can download both versions ? It will help others who are now on 3.0 and would have have saved me a lot of time.

Secondly, I appreciate the scale tips - I did see that in my scene, using the Quick Settings, QS did indeed change the scale to something less than 1 and probably explains why I didn't like the scale of the waves in relation to my ship's scale.

I have some more 'basic' questions - this is really basic and will help me understand, so please if you could, I'd really appreciate your help;

If I create a nice ship/ocean solution - why would I want to keep creating new ship solutions from scratch for different ships if all I was ever wanting to do was simply change ships ? I guess my question is, if I use the same Ocean solution that is in the ship.max for my own ship (only changing the Grid size so that it is big enough for my ship and change the cell size so I too have enough Total Cells) will I get the same 'looking ocean / waves / foam and splashes' as in that ship.max tutorial ?

Or must I also change other settings in there as well (i.e. foam, splash, waves etc) for each different ship I want to simulate ? To me, it seems logical that I shouldn't have to but then that leads me to why there aren't 'Presets' already within FD for this as I'm guessing that FD is used a LOT in ship/ocean scenes.

Also, to help me better understand also, if I replaced this ship with a speedboat, travelling a lot faster, would the FD solution need refining in the Foam/Waves/Splash areas ?? I would have thought that an Ocean is an Ocean and that is it, once it is set to behave a certain way it will do that for any object interacting with it ?

Sorry, I know these are basic (even weird !) questions and will clearly show that I am not understanding something, but I would love to see where in the Documentation this is all explained (and I will happily go and read that too ).

Many thanks for your help.

[George Barzinski]

Hi Jez,

we are trying to make Phoenix as user-friendly and universal as possible. After all, there are countless situations and in some cases, some tweaking and basic knowledge are needed.
So, in your case, you want to replace the ship with much smaller and faster vessel. What should you do after that? Well, there's a couple of things you should do/know:
- Reduce simulator size. That's ok.
- Reduce the grid resolution. That's ok too but would lead to different results. For example, bubble size would increase with smaller resolution. Also, there would be less detail in simulation and different fluid dynamics.
- Different vessel geometry would lead to different interaction with the fluid and different final result. For example, different kind of waves and therefore different amount of foam.
- Different speed - that would create really different outcome result. Because it would create different velocities in the fluid which would affect directly the size of the waves and the amount foam.
- Amount of the foam - if it's not enough you can increase the Foam Amount parameter or/and decrease the Threshold. Decreasing the Threshold means that the foam will be born easily (for example If you have slow moving vessels).

Additionally, you can read these articles:

https://docs.chaosgroup.com/display/PHX3MAX/Liquid+Foam
https://docs.chaosgroup.com/display/PHX3MAX/Liquid+Grid
https://docs.chaosgroup.com/display/...plash+%7C+Mist

Cheerz!

[JezUK]

Hi George,

And thank you too for your help - slowly I'm getting there !

So, from my understanding if you have one ocean, and two different ships both on that same ocean, say for example a 300m cruiser ship and a 20m speedboat, you would create two different FD solutions, with *different* settings. You don't set each vessel (cruise ship and speedboat) on the same water, with the same settings ?

Is my understanding correct ?

And therefore you play with the settings PER vessel to get the 'look' you desire ?

Change the vessel (from a 300m vessel to a 30m speedboat), and you will almost certainly have to change foam/wave/splash settings, because these are not universal settings for just any vessel on the ocean but are specific settings to each vessel ? Is my understanding correct ?

And as you mentioned, changing the grid resolution, affects the bubble size (increases) please can you confirm when you say 'smaller resolution' do you mean 'lower resolution' ?

Finally, please could you explain why when Foam Amount is 0 foam is still being produced ?

I will go and read the documents you link to now

Many thanks.

[Svetlin.Nikolov]

Hey,

You could put both vessels in the same sim, but it would save you some hard drive space, memory and sim time to have two separate simulators if the vessels are not interacting closely. If both simulators are in Ocean Mesh mode, they will combine their meshes and render as a single ocean.

If you have your vessels in correct scale relative to each other, the same simulation settings would suit both of them, either with two simulators or one common sim.

If you have your foam amount set to 0, foam cannot be born naturally, but still can be created when other particle types are getting converted to foam, for example, check the 'foam on hit' option of the splash particles.

Cheers!