Lighting an Interior Daytime Scene - Photographic Rendering with V-Ray for SketchUp - page 71

Again, with our Sun spotlight enabled, the GI (skylight) option would give us a very
acceptable natural daylight simulation. One of the drawbacks of using just the GI
(skylight) color swatch, however, (a drawback that also applied to our rectangle light
setup) would be the fact that we are lacking any real variation from the skylights col-
or contribution. When using the V-Ray sky map, we automatically get color shift and
variation in the sky map as defined by the position of the V-Ray Sun in the sky. This
is not so when using a flat color as we are here.
Another problem we see in this approach is the relative weakness of the occlusion
or contact shadows in the scene. As this was one of the strengths of the rectangle
light approach, this lack becomes very apparent here.
As with every aspect of rendering, the lighting choices available to us mean we are
constantly trading the benefits of any particular approach with its drawbacks.
Trying out the Dome light
One skylight option available that would certainly improve the occlusion shadows in
the scene would be the (new to V-Ray Version 2.0 for SketchUp), Dome light. This
light takes its name from the fact that it provides us with a 180 degree, hemispherical
dome of light that can give perfect skylight coverage to any scene. Now, of course,
the GI (skylight) tool that we have just been working with does exactly the same
thing. The big difference with the dome light, however, is that it doesn't need V-Ray's
GI systems enabled in order to work given that it is, in fact, a direct light source. This,
of course, is what gives it the ability to create much stronger occlusion shadows than
its GI (skylight) counterpart.
To take a look at this powerful lighting tool, open up the Day-
light_Interior_06.skp file from your Exercise_Files folder. This again re-
sets the scene, bringing us back to complete darkness in our renders.