Adding Photographic Touches in Post-production - Photographic Rendering with V-Ray for SketchUp - page 326

from the Chapter_10 folder in our Exercise_Files folder (this is just a copy of
the finished scene file from Chapter 9 , Quality Control ).
There are, in fact, a few ways we could go about creating a mask in V-Ray, but see-
ing as in this instance we want to be as quick and efficient as possible, we will take
what I think of as a brute-force approach. To do that, let's perform the following steps:
1. Open up the material editor, create a new standard material, and then right-
click on it to rename it Red .
2. Right-click again on the newly-named material, and from the Create Layer
flyout, choose Emissive (we will use this to give ourselves a self-illuminated
material in the scene).
3. Triple-click on the floor geometry to select it from inside the group, and then
right-click on the red material in the material editor to use the Assign mater-
ial to selection function.
If we were to render at this moment, all we would get would be a very long wait that
produced a render very similar to our existing final image—only with a red floor of
course. What we want is a perfect mask; a render that has a bright red floor with
every other piece of geometry in the scene completely black. To do that, let's open
up the V-Ray option editor and perform the following steps:
1. In the Global Switches rollout, disable the Lights and Shadows options
found in the Lighting section.
2. In the Materials section, we can uncheck everything.
3. In the Camera rollout, we need to uncheck the On option for the physical
camera.
4. In the Output rollout, we can click on the Output File browse button and
name our image Floor_Mask.exr , saving it to the Exercise_Files |
Final_Renders | Chapter_10 folder.
5. Finally, in the Indirect Illumination rollout, we can turn GI off and then hit
the render button up on the V-Ray toolbar.
What we get is a very fast render of our scene with nothing but a red floor and black
objects. This is a perfect mask for us to use, especially as the objects standing on
the floor are perfectly separated from the floor color.