@Hasdrubal I wish there was a way get the HDRI lighting to emanate from only inside a room.
Can you maybe turn the room inside out, bake it then flip it around again? Is that crazy?
I any case here's my scene with the area light replaced with a point light moved far away.
With the Attenuation Off there's no light fall off so distance won't diminish the light.
I used an HDRI for ambient light called StudioF I think was from one off our members.
PS: Point light intensity setting of 3
Uh, the main problem here is Cheetah. The lights need an overhaul.
In other apps it's possible to use Lights with texture or to create real "mesh lights" (not only emanating light from the texture, but, well, any object as a light source, also able to be combined with a texture). So you just use a hdri as texture for you light, and that's it. So you could combine as many hdris as you want (for example with "light cards"). I use area lights very often with the texture of a real diffusor, so it's reflection is the same as it would be inside a studio. And that adds realism.
Without that, I simply would use an area light for the window and a hdri for the inside (and as Frank mentioned, there are these portal llights, which don't emanate any light but just bundle the rays). That should function well enough (even if there isn't any window glass, which of course would be another level of realism, at the cost of rendering times. Sometimes you see the difference, sometimes not.
Here you have another problem. The picture outside doesn't fit the the inside (the colors are way overblown), and in a real foto you wouldn't see it as well as here (it would be hell of a lot brighter, looking at the interior, almost white). An the point light is the most unreal thing available in the world of 3d, only topped by a point light without light falloff. So I literally never use them ((it's good to have 'em around, though, in case you need some cheating). Sun light would be better, or the area light, which in my view harmonizes best with a hdri.
What you could try, though, would be to stitch two halves of an inside and an outside hdri together in the painting app of your choice. For realism the "outside half" would have to be brighter then the "inside half". If you position that light carefully enough, then you had just your hdri for the whole scene (but those two would have to fit together also from the light situation of the inside half). Never tried that out, never heard of someone doing it, never read about it. You'd be the first to try.
The actual problem isn't even the light. It's all the stuff inside a room, be that a bathroom or a living room. If all those objects are inside the room, you don't need an inside hdri anymore. But the idea with baking, well you can try, but I don't think that it's worth it and that it really would function.
And as a p.s. about denoisers:
I forgot to mention that one of the downside is simply, that they don't work that well with anymations. You can get a lot of flickering (the different apps sometimes have ways to deal with that, for example with adding the denoiser after each iteration ...).
( I doubt numerically will work on an angled wall like this.)
