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mranosa

Houdini Boat Wake Effect

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Hi guys :)

 

I have tried a lot to reach the boat wake by using collisions or velocity geometry ! 

 

Does anyone have a good idea for this ?(maybe some example file with some model or a hull!)

 

Thanks !

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3 hours ago, tamagochy said:

Add custom velocity to flip fluid at the nose of the ship. Its match more easy then collisions and not depend from the speed.

can u give me a good example file because i tried this and failed ?

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You should post your failed file so all of us could look at it and tell you what is wrong. That way you can learn from any mistakes you may have made.

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Ok I did a sim with collisions and tried to play with a lot of stuff to make it better and with 6 million particles ! I did it with some volume collision 

 

this is the sim

 

https://drive.google.com/open?id=0B8x1Z3zgTaL7bW5DOHNlOWpyM2s

 

 

it looks crazy somehow ,especially, when u try to do something like this by graham 

 

 

these are the hip file and the model used

 

https://drive.google.com/open?id=0B8x1Z3zgTaL7WU4wWHA4NEJPa1kvv

 

 

sorry for being late and i hope someone help me :'( 

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I have downloaded his file and animated the grid pump and i had the result i posted above which is this 

I didn't like this result at all ! 

 

 

Edited by mranosa

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I am not sure what you are expecting? it looks like the animated pump is doing its job and creating the wake from the bow of the boat. Are you wanting more of a wave? More splash? You are not limited to using the same geometry as in jeffs file. You can make your own and edit it how you want to.

The great thing about Grahams videos is that he does solver settings that accompany his RnD. Look at those videos and see how the wave is influenced by changing certain parameters.

https://vimeo.com/68531266

 

 

 

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no , i have changed and tried a lot but there is a big difference between the video of graham and mine ! 

my try has a big wide wave which makes the foam very bad ! 

look at graham's video and compare them ! the difference is so big !

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I am really disappointed that noone helps me at all :((((

 

I want to acheive something better but it seems there is no chance :(

 

I watched this video and i can't do anything more to reach this effect at all ! it seems like a secret or something very private !!!

 

 

i don't know what are the GVS and Oversampling parameters :( and i can't have a collision otr effect like this 

 

please please i am very disappointed and about to leave everything 

 

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Your tests seem to be of significantly lower particle resolution than the references, that might also be a factor?

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Here is my attempt at the effect. The particle separation is fairly high so the results are coarse. Feel free to lower the particle separation and re-sim. I have not included any whitewater, you can add that on top once you settle on a final particle separation. I have installed the pump, as best to my ability, following the instructions in the Jeff Wagner "flip_pump_bow_curl" hip file from the above link. I have enabled OpenCL on the solver to increase calculation speed. If you experience crashing try turning that off in the solver. I have linked the Division Size of the ship hull volume directly to the Particle Separation of the Flip tank to keep things balanced but as you drop the Particle Separation you may want to de-couple these two parameters as you may not need that much resolution on the hull volume. You could also just Clip off the top half of the boat, unless you expect waves to roll over top.

I think eetu is right about the resolution. You really have to lower the particle separation get hi-quality results.

Untitled-1.jpg

ap_large_ship_wake_with_pump_1a.hipnc

Edited by Atom
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Here is an integration attempt with the Jeff Wagner's pump geometry fitted to the hull of the ship. I did a little more shaping of the bent grid to conform to the ship hull better. I kind of toned down the amount of velocity that the pumps send out along those curved guides to emulate the larger scale of the ship. After all the ship is supposed to be very large. The ship model at a scale of 1.0 seems to be real world units, however, when I tried to scale up the simulation to match the ship it failed to work correctly. So in this example scene I have scaled the ship down to fit the size of the working pump. This goes against most suggestions that you work at real world units with flip but hey this is just for fun. And this technique of using curved pumps is fun to mess around with. I could see this being used for any kind of geometry that you want to skim across a fluid surface. Such as a water skier, a jet ski, or even cartoon characters.

Untitled-1.jpg

ap_jw_flip_pump_bow_curl_1a.hiplc

Edited by Atom

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Nice ! 

 

I was trying the first collision solution with high res (40 million ) It was the same as my one and i can tweak it more to look better , but yeah i think i will see Jeff's solution and compare them ! 

 

Thanks :) Again , i will send a reply with the result !

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I tried ur file :)

there is something lost ! 

The wake doesn't look really well like any video ! it is a punch of noise and the wave is not going backward in good way .I tried jeff's scene as he did as well and i don't know how to get a wave like the videos i shared with this :( it always looks hell and nothing fancy happens although i have tried a lot with many number of particles and everything looks so bad :( (Not production stuff or even good looking)

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That is the thing with FLIP, half of the magic is in the materials. Have tried reaching out to Vladimir or Graham on Vimeo? Maybe they can give you some tips...?

I also wondered if the trailing wake is actually caused by spinning propellers. It might be a dual effect you are seeing in those videos. You could try separating the propellers from the ship, making them rotate and turning them into Static objects. Then in the sim make sure the Static object is set to deforming with a good collision volume resolution.

Edited by Atom

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