I have made this pool using a subdivision surface modifier. It looks well enough as it is, right? What is the correct way to add the water surface to this? Would I simply create a square mesh plane as a separate object, without a subdivision surface modifier, and just lower it into the pool and let it clip through the walls of the pool? Or is there a better way to do it? I want to make a television also and I suspect that I could use the same principles to make that. But for now, I just want to know the right way to add the surface of water, somewhat below the lip of the pool, preferably at approximately the height of the selected loop shown in the image.
You can set the 3D Cuser to that location and create a plane with Add to use it.
I don’t know about the ‘correct’ way… but adding a new plane is fine… you can let it clip through the walls or add a Boolean modifier to cut off the overlap.
I found some interesting tutorials on fake water caustics which would really help you make this look perfect… there is one on YouTube that covers this exact scene pretty much… google it or let me know and I will dig it up or share my file
Ways are many, but you must know what you want to achieve. To render an image you could e.g. make a face as you already have the edge loop, then give the face transmission and/or transparency. Maybe some texture. With an anim you could e.g. keyframe ocean modifier.