Lighting an Interior Daytime Scene - Photographic Rendering with V-Ray for SketchUp - page 68

These kinds of drawbacks have to be carefully weighed against the quality and flex-
ibility (or indeed lack of such) that we get from the fill light solution when we use this
particular approach. Such considerations become especially important given that, as
we have already noted, this particular method for creating a skylight effect is not the
only option available to us when using V-Ray.
Another approach would be to actually mix and match the use of specific V-Ray light
objects such as our Sun spotlight with the default environment GI (skylight) that we
used in the previous chapter. To test that out with this scene we will need to first of
all disable the sunlight component of our Sun & Sky system.
To help us explore this approach, open up the Daylight_Interior_05.skp file
from your Exercise_Files folder. This version of our interior scene takes us back
to being in complete darkness once again, ready to build up a lighting solution using
the GI (skylight).
One important difference between this and the rectangle light approach, one that we
need to think carefully about, is the fact that the rectangle lights we were dealing
with initially are recognized as direct light sources by V-Ray. This means we get light
whether V-Rays GI systems are enabled or not. However, the GI (skylight) is an in-
direct light source, and as such, can give no light at all unless the GI systems are
enabled.
Clearly, the first thing that we need to do in order to work with that option would be
to turn the GI systems on. To do that, perform the following steps:
1. Open up the options editor from the V-Ray toolbar.
2. In the Indirect Illumination rollout, put a check in the On box.
3. Next, click to open up the Environment rollout.
4. Put a check in the On box for the GI (skylight) option.
By default, the GI skylight (with the TexSky map applied) has a V-Ray Sun element
already enabled, which, of course, we are not using in this instance. To disable that,
we need to perform the following steps:
1. Click on the map button next to the GI (skylight) multiplier spinner.
2. In the V-Ray texture editor, inside the Default Sky Options area, click on the
Sun drop down and then choose the None option.
3. Click on OK to exit the V-Ray texture editor dialog box.