How to set up a daylight effect
by Jason Saunders
Whether I am creating an interior or exterior, I always create sky
environment spheres. The trick is to use a high res sky map and turn the
texture output to illumination instead of colour. Add a colour constant to
the same shader and make it black. Now when you render in GI you see the
sky without any alteration to its original colours, but it is now projecting
illumination values based on the colours of the sky image. Its a poor mans
HDRI, but quite effective even on interiors.
You may want to add a curve object to the shader with illumination
input/output to take greater control over the illumination output in your
I also use a spot light set as a distant light source for my sun.
With these interiors I have had to use interior spot lights to initialise
the materials. However it is possible to get nice renders without any
interior lights at all (as with 'image 4 - Nell Interior' in the residential
example section on my site). Play around with ramping up the sun light
source and for best results you must adjust the 'GI-brightness control'
curve to get the ambiance you require.