"Constraints of gravity." Heh. Yah, there are so many tricks I can do in 3d that I wish for in my regular job lighting the stage for live theater. The biggest being that 3d lights aren't visible. Not only don't you have to hang them, or run power to them, but you can put them right in sightlines, even right in front of the camera, and no-one will see them. Another lovely cheat is fall-off. I've used spotlights several times of late to punch up an important element in the scene...and with a couple test renders you can tweak the fall-off to where the light just hits the target then stops, magically, in the air before it would cast an ugly shadow on the wall. Most of my scenes are three-point, plus practicals, and often a rim light and some specials. The way I usually set it up, is first I determine what will be the strongest and most dramatic light in the scene; moonlight from behind, a light through a window, a glowing gem at the center, whatever. I set this light up first, with no other lights, and do several renders until I like the shadows and so forth. Then find the second strongest, usually complementary. If the Key was sunlight, the Base is backfill from the blue sky. If the Key was the direct light of a floor lamp, the Base is the warmer scatter coming back off the floor. Lastly, I plop in a fill; soft shadows or even no shadows, more-or-less from the camera direction, filling in the gaps where the other two lights meet. That's in some neutral color (like a pale lavender), and at a very low level. Carrara gives you the additional tools that any of these three basic lights can be the sky dome, the radiosity-like GI scatter, an HDRI map, a large square with a glow channel, etc. I've done several outdoor pics that were just sky dome, a single distant light, and GI. What I like about three-point thinking (even if the final design ends up being twenty instruments from six directions, which is usual for me in theater), is that it asks you to find the most dramatic way to light, the light that most tells the story and leads the eye, and the light that most enhances the total look of the scene (the time of day, the season, interior or exterior, moody or friendly, chilly or warm...) Sorry. Pre-coffee ramble. And I'm facing a long day of moving real-world lights that weigh thirty pounds each and have lots of hard steel to bark knuckles on.