Anyone been able to get a good results with the Wake tool ??

[zylphyr]

What exactly are you trying to achieve? A boat wake, ripple etc?

I've been using it for a while now (in production), and have found that keeping track of scales/sizes is a good idea ;) the quality of the fluid must also be scaled to the size of the fluid.

Also, most of the tweaking usually takes place in the fluidnode and not on the emitter...things like damping; dissipation and diffusion are things to look into.

Take a look at the pond wake example... you'll notice that the wake depends on the transformation of the emitter (not by expression or drivenkeys, but simply by physics). Checking out the jitter function on the emitter may help you out if your emitter is standing still.

Let me know what you are looking for and I may be able to help you.

[Kaiser_Sose]

Are you trying to create ocean waves or the foam

Try putting a fluid loppable movie in the bump channel of the ocean plaine

[Kabab]

I am trying to get some small to medium wake caused by a large navy type destroyer.

The results i get a varies but they generally seem to be to circular for my liking.

Notice on this picture how straight the wake is and how steep the angle is compared to the hull, i am trying for something like that.

http://www.fas.org/man/dod-101/sys/ship/ddg-77-okane-arr.jpg

Also can you get foam like this ??

http://www.fas.org/man/dod-101/sys/ship/jsmccain.jpg

The foam i get just sorta seeps out of the emiter it does get pushed out with the wake.

Is there anymore documentation around ?? then whats in the help because the help isn't very helpfull..

Thanks :beer:

[zylphyr]

First of I would turn on shaded display of the wakeFluid to "As render". Helps you see what you're doing when making the wake. ;)

Turning on "use height field" can also be useful while tweaking the motion. Turn it off for rendering. (it scales the displacement (fluid) , so you might get unwanted results in rendering).

Under dynamic simulations, make sure the solver is "Spring Mesh"

U need a big fluid, with high resolution, so you're wake can travel naturaly.

Place the emitter in front of your boat (it's size should match the with of the boat at the tip, but tweaking will be necessary).

Put some animation on the emitter to get some motion on it. When standing still, the wake emitter isn't much fun (unless you enable the "Jitter" function on the emitter)

You should now be able to see a greyscale representation of your wake. (I realize that all of the above probably is old news, but what the hell...)

go into you're fluid again and start messing with the damping factor. The higher damping, the longer and narrower the wake becomes. higher value on the dissipation will diminish your wake more quickly over time, but without effecting the shape (see: damping).

The fluidDropOff (on the emitter) should also be checked out. it works somewhat similar to dissipation. Density controls the overall effect of the wake, together with rate ( I’m not sure if anything other then a multiply actually happens between them).

as far the foam goes. Much of the same applies. here you might want to change the default solver (navier-Stokes) to Spring mesh, if you want the foam to follow the wake. Basically the OceanWakeFoam works as a displacementmap for the foamOffset in the oceanshader, being trigger by the foam emission and threshold. Tweak your foam for rendering here. However this foam is (as I'm sure you know) just colour and disp., so if you want flying foam use the OceanWakeFoam as texture (on a nurbsplane) for particle emission. (Emit from object, map texture rate with fluid).

Maybe not much help here, but you really need to break it out and start messing around the get some decent results.

[Kaiser_Sose]

Originally posted by zylphyr
However this foam is (as I'm sure you know) just colour and disp., so if you want flying foam use the OceanWakeFoam as texture (on a nurbsplane) for particle emission. (Emit from object, map texture rate with fluid).



Sounds like you have been using mayas dynamics for a while now. can you describe in more detail how you would map a textures rate with a fluid

Also, do you know how to take an animated file, map it as a bump map, and then match it to a turbulance field



Thanks

[Kabab]

Thanks alot for you reply i was kinda lost but this helps alot..

To bad this info wasn't in the doc's :hmm:

edit
forgot to add

:bowdown: :bowdown: :bowdown: :bowdown: :bowdown:

If your in sydney sometime let me know i owe you a beer or 2 :)

[zylphyr]

http://www.aliaswavefront.com/en/Tmpl/Maya/html/index.jhtml?page=/en/Community/Download/fluids/maya5.shtml&style=normal

bunch of wake/pond/fluid example scenes...

what you need.

[Kabab]

I still can't get the foam the push out like that 2nd picture any suggestions ?

[zylphyr]

Looks like I was a bit too quick on the trigger regarding texture rate particle emission using fluid texture. Apparently Maya can't evaluate the fluid texture for texture rate emission (same with 3d textures). :thumbsdow

The workaround would be to either bake the fluid texture on each frame, or render out a top down view of the texture and map that to the texture rate...the latter is probably the best solution.

Kabak: If I can find the time, I’ll whip up some foam for you and post it…

Kaiser: I'm not sure I understand what mean by :

"... take an animated file, map it as a bump map, and then match it to a turbulance field"

Match what? the placement, the frequency, the amplitude. and what should be matched to what? I seem to be confused...;)

[Duncan]

I would recommend using the ocean wake, not the pond wake. On the foam fluid for the ocean wake the turbulence parameters along with a bit of diffusion can create OK looking foam. You may wish to increase the resolution on the foam.
The speed of the waves can be adjusted by changing the simulationRateScale on the ocean wave fluid. For the large boat scenes you probably want it to be quite low.

Also the commands fluidVoxelInfo and get/setFluidAttr can be used in various ways inside expressions to have particles emit from fluids or emit into fluids.

Duncan

[zylphyr]

Ocean is the way to go for what we're looking for here... maybe I didn't make that clear :p

Didn’t know about the "Simulation Rate Scale"... suddenly life got a little bit easier. (it can be found under "Dynamic Simulation" on the fluid).

Duncan: I talked to alias support yesterday... I don't think they had heard about "fluidVoxelInfo and get/setFluidAttr"... at least they wouldn't tell me about it. Maybe you could point us a little bit further in the right direction with the expressions?

[Duncan]

For example if you wanted emission based on the fluids foam intensity you could do the following:
*emit particles from an object grouped with your boat

*in the particle create expression use fluidVoxelInfo to get the fluid voxel index at the particle location( use 0 for the particle y position) Find the foam value from the fluid at that point using getFluidAttr. If the value is below a threshold then kill the particle( make its lifespanPP 0 or -1). If the particle is above the threshold use colorAtPoint passing in the oceanShader with the particle location to get the height of the ocean at that point. Set the particle y value to the ocean height( perhaps plus a little). (look at the ocean surface locator expression to see how colorAtPoint is used.. also check out the command node documentation).

*in the runtime expression you can kill the particle if it goes below the ocean, as well as using fluidVoxelInfo and setFluidAttr to add a bit of density into the foam and/or wake fluids.

At any rate check out the doc on these commands.

Duncan

[Kabab]

Great thanks for your help i noticed the simulation rate setting while looking at one of the examples, that has helped with what i am doing.

But i still can't get foam that gets pushed out, i only get foam that trails. Is there anyway to get the foam to be pushed out away from the hull of the boat.

I am using the ocean wake..

Thanks for your help..

[zylphyr]

Thanks Duncan. Always nice to get a little push in the right direction. :)

[mechaniac]

i noticed that when i set the fluid container to "as render" it displays very large displacements of the wakes.
but this can not be seen in the fluid preview plane and also not in the rendering!

any suggestions?

[zylphyr]

pump up the alpha gain on the fluid texture.

[mechaniac]

that was a really helpfull one!

thanks a lot!

[mechaniac]

another problem i have:
though i have put temperature to dynamic grid and heat turned on on the emitter (40) i dont get any foam on my water....
have i overseen anything?

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