UE4 - How would you make a huge splash of water?

General Discussion
#1

I am trying to create a hug splash of water like the water you see when a whale breaches. I think that it resembles smoke more than water so I am wondering would you use any base color, or make the whole thing with emissive color?
Also I dont see any need for refraction or normal displacement?

Do you agree, would you make the whole look just with emissive colors? and maybe a smoke sprite sheet?

Also, How can I make the surface of the water push up as the whale surges up. Can I use a DecalActor with a displacement shader attached? So that I can position it at just the right place?
So far it appears that a material with a Decal Actor has to have a material domain called Deferred Decal, correct? it also appears the decal doesn’t accept Displacement!? is this true?

If I cant use a decal how would you create this kind of displacement?

#2

for the displacement you probably want to do this inside the water material and dynamically position a mask(texture with warp mode to clamp or a spheremask) at the splash location.

#3

I am not sure how to dynamically position a texture, but if I was to guess with my limited knowledge. I could use a panner node with scalar parameter plugged into X and Y. Is this how you would suggest I do it or is there a simpler way?

#4

assuming your water uses world space coordinates and your texture sampler is set to wrap: clamp you can just add the world position of your splash location(through a vector parameter) to the UVs before it goes into the texture sampler.

#5

Water splashes are really tricky to get looking right. I find its not as simple as just using one type of sim such as smoke or particles. Usually i layer several textures together, one for the liquid itself and one for the mist. The liquid effects are usually generated from particles that have been meshed and rendered out with normals for the specular. For the mist i usually just use fumefx with all the sim quality settings turned down as low as they go.

Here are a couple water sim videos, it may give you some ideas. :slight_smile:
https://vimeo.com/search?q=water+explosion

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#6

Id also suggest to look at the water-vfx from the infinity blade content, its a good starting/inspiration point.

Sadly I dont have the time to explain in detail, but splashes in ue4 shouldnt be too hard:

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#7

How can I tell if my static mesh object uses world space coordinates ? And what are the other coordinates called UV maybe ?

#8

I just made a large BSP flat box that will be my ocean surface. By default do BSP objects have world coordinates?
I want to position the displacement texture, but cant see it to position it. I’ve clamped the texture so that it doesnt tile.
Any ideas how I can do this?

#9

there is probably a cleaner solution to this, but it should work.

https://dl.dropboxusercontent.com/u/107682595/Unreal/Texture.png

If you do not necessarily need a texture for this you could use a spheremask instead. much simpler and resolution-independant.

https://dl.dropboxusercontent.com/u/107682595/Unreal/SphereMask.png