How To Have Nav Mesh In The Air

Right now I am attempting to make a Fish AI that will move to random points in the lake.

I am using the “Water” plugin in unreal to make a lake and I am placing a nav mesh bounds volume within it for the Fish AI to find its path. However, because I want the fish to move through the water (rather than on the ground like a normal NPC) I want to have the nav mesh be floating and get a random location within the entire volume but because it doesn’t overlap with the floor, nothing happens (if I press ‘P’ there is no green area that indicates a navigable area). Please let me know if you have any suggestions or a different approach for this. Thanks!

Unfortunately, things like fish or birds will likely require a linetrace-based navigation system. The Blueprints example project (here) has an implementation of this for butterflies. You could also try the “Don’s Flying AI” plugin, but I’m not sure how well it works for fish.

Thanks for the response. I copied another projects approach for AI birds. This does exactly what I want in terms of random movement. Basically, you just need to size a box and the AI will choose a random point within it.
I will definitely take a look at your suggestion because I am still new to this AI movement concept.