ask help for underwater sunlight fx

[Guest yunli56]

 

Is anybody know how to do the underwater sunlight like the picture in after effects?

 

I am very appreciate if anyone can tell me,thanks!

[Guest firemind]

That is called caustics and there are a myriad of plug-ins/ways to fake it. From using an animated map in front of your lights all the way up to physically correct caustics in a 3D program.