I've come back to this as part of my fill light setup review... but I'll leave that part of it out for now as this works with or without GI. Have a look at the shadow of the tree cast by the sun in the attached image. You'll notice that it is darker under the canopy of the tree, than out in the open. Now get your nose off the monitor, give it a wipe (the monitor
) and lean back. Now you should be able to see a faint shadow under the canopy of the tree as well.
Setting this up with a single light is quite tricky as it's a big balancing act between getting a dark enough shadow and overpowering the sunlit areas with the extra light. The wider you make the soft shadow, the stronger the light has to be to be able to see the shadow... and the worse it makes the rest of your image look.
This is where I borrowed some stuff from my fill light setup (with a slight twist) to simplify the process. Taking the available properties of lights inTG2 into consideration we can split this dilemna into separate components and solve it with only two lights.
1. For sunlit areas we don't want any additional light (with GI on) or only a small amount of light (with a fill light setup) - Duplicate the light and stick a minus sign in front of the intensity.
2. But this will remove the shadow as well - turn all shadows off on the duplicate light
3. I want the shadow to have a different colour - choose a colour and look its HSB value (Hue, Saturation, Brightness). Invert the Hue value only (for windows, add or subtract 120... whichever gives you a positive number < 240) ... apply the colour to BOTH lights. (Try the red decay colour)
4. (For fill light setups) I want to add a slight colour to all light from above that is different to sunlight AND have a complementary colour in the shadow under the tree - increase the intensity of the duplicate light slightly (duplicate light doesn't completely cancel the soft shadow light)
This provides you with separate control over softness, intensity and colour of the shadow with a minimum of variables. Dead simple and easy to control.
The soft shadow in this example is only 30 degrees.... should have made it more like 60
To use this as an example of how the control is simpler.....
The intensities of the 2 lights in this example are 1 and -0.7
In areas under open sky but shaded from the sun the total effect is that of a warm light with an intensity of 0.3.
Areas shaded frm both the sky and the sun are darkened by 0.3, and have a sky blue cast.
Now I've increased the soft shadow diameter to 60, which will make the shadow much lighter.
Increasing the intensity of the shadowed light to 1.5 gives me a shadow with the darkness I want, and to restore the colour balances I had, the difference in intensities needs to be 0.3 ... i.e. the second light now has an intensity of -1.2 (inset in attached image)
The shadows have been tweaked while retaining the rest of the lighting completely intact without guesswork
Shadows near the trunk are now slightly darker, while shadows at the edge of the canopy are roughly the same.
I still have some more work to do on my fill light setup before I post the updated version. I'm not entirely convinced by my colour selections yet....