water Underwater expression

[DogFreak]

This is my first post. I'm sorry if I'm wrong about the conventions here.

I'm trying to create an animation that goes from above water to below water.
I want to make a splash when above water and a bubble when underwater.

For the bubbles, I looked for tutorials on Youtube and found that most of them were created with polygons.
I was thinking of using particles for the water, but is it possible to use polygonal bubbles for the water?
Is there a better way to do this?

Also, if you have any tutorials to recommend, please let me know.
Sorry for my bad English.
Thanks for your kindness guys:)

[underscoreus]

Heyo!
I'm by no means an expert here so if anyone else wants to chime in with their ideas or tell me that mine are terrible be sure to do so!

So just to confirm, you are trying to make a shot where the camera goes from above water, then "hits" the water surface causing a splash, and then after that the camera is below water and while the camera is underwater you want to have some underwater bubbles. If I missed something or misunderstood please correct me, but for now, I'll continue with the assumption that what I described above is what you are after.

So for this kind of shot, I'd recommend dividing up your shot into separate components and then bringing them together at the end, either merging your setups together before render or rendering them separate and bringing them together in a compositing program like Nuke, After effects, COPS or Fusion (or anything else). 
To break this up and make it as easy as possible to work with I think I'd divide it up like this:
- Ocean surface/splash sim don by itself. Just make a simple FLIP flat tank and drop/animate a sphere into it (by dropping I mean just making a super simple RBD sim of only a single sphere falling then importing the result into the FLIP sim as a result). For this you might even be able to get the results you want by using and adjusting the "Crown Splash Particle Fluid" shelf tool since it is already set up to make a splash from the get-go. Then depending on the scale of your splash, is it supposed to be a 1 meter tall splash or just 10 centimeters tall, you might want to do an additional whitewater sim to add foam and spray to the liquid surface.
- Next, I'd make the underwater bubbles in a completely separate setup. Like you said most people use volumes here that they then turn into polygons for rendering and that is probably the best/easiest way of getting the deforming, blobby shapes. If you are more after more "individual" bubbles, not so deforming and blobby you could probably just copy sphere onto points or particles moving but that comes down to how you want the bubbles to look.
- Lastly for the background behind the bubbles when you are underwater it'll depend a little on how you imagine it looking. If the scene is out in the middle of the ocean and you can't see the ocean floor then I'd recommend trying to make a background in post with After effects, Nuke, etc etc. It'll mostly just come down to making a dark blue to slightly lighter blue gradient and adding some shimmer. Tim's video here is a great example of that.
If you can see the ocean floor however I'd recommend making a fog volume that has a lower density near your camera and that gradually becomes denser and denser the further away from the camera it gets. Doing that and adding some blue-colored tint to the volumes volume shader will hopefully help you get the same look as in an ocean shot where tons of dirt and small particles obscure stuff the further away from you it gets.

Hopefully, that does not all sound like gibberish or like it is completely undoable.
If any of it was unclear or you'd like a more detailed explanation of one of the things I mentioned just leave a reply here and I'll have a look when I am free!

Good luck! 

[DogFreak]

Hi,Underscoreus!

Thank you very much for your kindness answer！

I think I got most of what I wanted to say across.I'm attaching a picture of what I want to do just in case.

I'll try your idea,when I get home! Thank you so much

Edited May 7, 2021 by DogFreak