Fluid simulation

[mcvltd]

I want to create a fluid simulation of a boat going through the water, producing a nice wake behind it.

Does anyone have any ideas on how I go about creating the water part of the simulation?

[Ivaylo Katev]

actually the simulator is gasseous, we are working over a liquid extension, but in the current version you can not perform full capable liquid simulations. of course some liquid-like results can be achived using heavy gasses, see the pool example, if this is good enogh for you go ahead

Regards,
Ivo

[mcvltd]

Yep, the pool example is what I was trying to replicate. It seems that to achieve this the box has to be filled before the simulation starts. Any tips on how to do this? It looks like it's done by some scripting, but having never done scripting before, it doesn't seem obvious what to do/write in the scripting window.

[Ivaylo Katev]

you can do this without script, using texture. go to mapping rollout, set the "init" checkbox for the desired channel, and put into the slot a texture giving the initial state of the channel.

[mcvltd]

Thanks Ivo, will give this a go.

[mcvltd]

I think there's something very fundamental that I'm missing here. I'll describe what I'm doing to setup the simulation box so you can see where I'm going wrong.

1- create simulation box in viewport
2- uncheck wind from movement
3- change stop frame to 5
4- change conservation to 50
5- change vorticity to 0
6- (in rendering rollout) check geometry mode and solid mode
7- (in mapping rollout) check init on the temperature
8- (in mapping rollout) add a texture in slot - I'm guessing as I want the box to be full then this has to be white in colour? white = full, black = empty?

After I've done all this the box doesn't fill up.

[Ivaylo Katev]

I'm guessing as I want the box to be full then this has to be white in colour? white = full, black = empty?

not exactly
the initialization just takes the brightness of the texture and places it into the channel. for "liquid" you need cold gas, let say temperature 1, for "air" you need normal gas, with the environment temperature which is 300 . the easiest way to form this is to prepare black-white texture, with black liquid and white air, and set an output map with offset=1 and multiplier =299

[mcvltd]

Wow, you clever guys don't make it easy for us thick people!

I've set up a gradient in the initial temp slot now, which seems to work.

But my biggest problem was not being able to see the simulation preview. The temperature value in the preview rollout was set to 1000 so when I reduced this to 300 the simulation became visible. So we have to match the preview temp value to the highest value we've set for the initial temp.

I'm starting to get some results now, thanks!

[Ivaylo Katev]

Wow, you clever guys don't make it easy for us thick people!

don't forget that phoenix is not intended for such kind of sims, when we add the liquid extension all this temperature tricks will be unnecessary.

[mcvltd]

Ah, ok. Fair enough. Can't wait for the liquid extension!

Just in case you guys need some suggestions for the liquid extension, here's my wish list -

A sea surface object, very similar to the dreamscape one except with far better/more controls over waves and motion.

Settings to fiddle with would include -

- fine detail noise
- short 'choppy' wave formations
- medium size wave formations
- large swell formations (all of the above would be able to be combined)
- 'pointyness' of wave
- breaking wave (ok that may be a little hopeful)
- Foam
- interactivity with objects (boat wakes with associated foam - for multi-hulls as well as mono-hull boats)
- Spray
- sea floor depth and colour (including a slot for image maps)
- animation presets for calm day, strong wind, gale, storm.

=)