Quality Control - Photographic Rendering with V-Ray for SketchUp - page 301

Working with the Image sampler

controls

Although we have saved our GI solutions to disk, we haven't yet set them up to be
used at render time. As we are now moving on to tweaking controls that can have
quite a significant impact on overall render times, now would probably be a good time
to go ahead and do that. This will help reduce the time it takes to produce our test
renders. To do so, let's perform the following steps:

1. In our Irradiance map rollout, go to the Mode section, which is just above the
On render end controls, and set the Mode dropdown to From File .
2. Next, we need to click on the File browse button to the right and select the
Irradiance map that we saved to the disk in the previous steps.
3. Repeat these same steps in the Light cache rollout.

Whenever we hit render now, rather than starting with GI calculations, V-Ray will jump
straight to the final image sampling phase. Before rendering though, we also need to
disable the override material. So, let's perform the following steps:

1. In the Global switches rollout of the option editor, uncheck the Override ma-
terials option and also enable the Glossy effects control.

Before we go ahead and make any alterations to our image sampling settings , we
do need to understand that the image sampling settings we use here will play a major
role in both the final quality and speed at which our rendered frames are produced.

To cover a variety of render situations, V-Ray offers three image sampling modes with
which we can work: Fixed, Adaptive DMC, and Adaptive Subdivision. In the majority
of cases, and certainly wherever we are making use of noisy effects such as blurry
reflections, refractions, and soft-edged shadows, Adaptive DMC (the default) will be
both faster and yield higher quality final results. So, for those reasons, this is the mode
that we will be working with here.

In fact, with our GI maps set up, let's go ahead and take a test render so that we can
make use of it in our evaluation of the current settings.