OK, so here is the latest Carrara thing that has got me scratching my head...

I've been having pretty good and relatively fast results when rendering objects in an open environemnt with HDRI for lighting (+Caustics,  -Light Through Transparency, +Indirect Lighting), but my tests reveal that the same will not work for an indoor scene.

What I like about the HDRI and Indirect Lighting is the natural bounce I get using this method. But with over 3 hours for a low resolution test render of a simple base scene, it is clearly not going to work out for the scene I have planned. Not if I want it to finish rendering this year.

The effect I am looking for is the softened shadows from the window freames + the bounce filling the room with natural ambience (darker in corners, bends and small places like furniture openings, lighter in open wall segments).

I was able to get the soft shadows from the windows by using a spot light with soft shadows (best or they get line separations) - 3min render.

I was able to get the amient bounce by using a white glow plane instead of the windows and rendering the Indirect lighting at 100 %, but that is a 4 HOUR render on the same small size!

I can kind of get what I want by combining the 2. But once I set up and populate my scene, the render times will get prohibitevely expensive, especially for the resolution I need.

I am attaching the desired result combination here and I will attach the components in response messages.