How to build a underwater environment?

Hi! I hope to build a underwater environment for the research such as AUV/ROV, I have build a liquid cube with Action Graph, but I found that anything in this cube will be push out from inside.
How can I solve this problem? And is this way will be possible to build a environment for AUV and other underwater robots research?

If you are seeing things in the cube be pushed out, did you apply rigid body to the object?

If you use Colliders Preset, items can pass through a pipe for instance.
With Rigid body enabled they push out as you mentioned.


If you did apply Rigid body, uncheck the box for Rigid Body in Physics.


Thanks for reply! I try your method and fix the issue that the cube will be push out.
But I found that the cube is forced as normal space rather underwater environment, so is this a right method to simulate an underwater environment?