How to make water not to pass through the the bottom surface of the floating object?

[Cheburash]

Hi
I made an ocean using ocean modifier, and placed into the ocean floating object - basin, using this tutorial: https://www.youtube.com/watch?v=11F1NRpqrzY
How to make water does not pass through the bottom of the basin?

I tried to use the basin as a dynamic brush and water as a dynamic canvas mode “displace” mode, but ran into an unexpected problem:

For some reason, if the object have “no cap,”, if there is no plane above the surface of the water - it draws bad in dinamic paint mode .

I found this problem after I chenged dinamic paint mode from “displace” to “paint”. I did it, because I could not understand, why does this method works bad in my case.

Here are two screenshots to make clear what i mean.

In the first screenshot the sphere has a polygon on top:I

in the second screenshot the sphere has no polygon on top:

How to fix it and make make water not to pass through the the bottom surface of the floating object?
Thanks in advance!

[Secrop]

The dynamic paint treats closed objects as volumes, but open objects (with no caps) as just surfaces. In your specific situation you can use some hidden object, linked to the original, to give dynamic paint the volume information; and then, use the resulted map as a transparency mask.

[Cheburash]

Thank you, it works!