Diving Straight into Photographic Rendering - Photographic Rendering with V-Ray for SketchUp - page 33

The one we are specifically interested in would be the Color (float) option. Whenev-
er all three numbers in this readout go above the value of 1, which is pure white in
floating point terms, then we know that what we are looking at is one or more super
bright pixels in the image.
Sometimes, we can use these to good effect in our renders, especially when it comes
to using the new Lens Effects feature of V-Ray Version 2.0. At other times, however,
the burnout these super bright pixels cause, particularly in areas where direct light
falls on an already bright texture such as our white walls, can be extremely undesir-
able. This means that it will always be useful to know which V-Ray tools can be used
to help deal with this. One set of such tools would be the color mapping controls.
However, before we go ahead and make any changes, I am going to open up the
Ch01_06_Tweaks.skp file from the Exercise_Files folder, which again picks
up from where we currently have the scene. (Again, feel free to continue on using
the current file, if you prefer.)
To deal with our super brights, let's perform the following steps:
1. Reopen the option editor by using the button on the V-Ray Main toolbar.
2. Inside the dialog, we want to open up the Color Mapping rollout and select
the Exponential option from the Type drop down.
3. We also need to set Bright Multiplier here to a value of 1.0 instead of the
default 0.8 .
This simple change in the color mapping type will prevent any of the RGB values
in our image from climbing above a value of 1. Another effect of this color mapping
change is that our rendered image will become a little less bright and the RGB values
of our extremely blown-out sky will drop to levels below 1, meaning that we can now
see a little bit of blue in there!
Another lighting tweak we might want to make at this point is in connection with the
current positioning of the direct sunlight in our view. At this moment in time, the sun-
light coming through the skylights is creating one or two bright spots on the left side
wall, which are looking a little messy and may need cleaning. We can do that by
basically shifting the Sun a little in our scene. To do that, we need to perform the fol-
lowing steps:
1. Open up SketchUp's Shadows control dialog from the Window menu.