Graphics Programs Reference
In-Depth Information
available for download from
www.sybex.com/go/intromaya2011
. However, all the scene files
for this exercise are on the topic's CD for your reference. Once you download the exer-
cise, you can use Adobe Acrobat and the scene files on the CD to run through this living-
room exercise, where you use simple GI techniques to explore this powerful rendering
option in mental ray.
Image-Based Lighting
mental ray also brings image-based lighting (IBL) to Maya. This method of lighting uses
an image, typically a High Dynamic Range Image (HDRI), to illuminate the scene using
Final Gather or GI. Final Gather is a form of global illumination that relies on direct as
well as indirect illumination. Direct illumination calculates the amount of light coming
directly from lights in the scene and renders the result. However, it misses an important
aspect of real-life lighting: diffuse reflections of light. Indirect illumination happens
when light bounces off objects in a scene in order to reach and therefore light the rest of
the scene—that is, diffuse reflections. Final Gather is typically a faster way than GI to get
indirect illumination in a scene.
We'll briefly touch on Final Gather here as we explore Physical Sun and Sky lighting in
the next section. However, we'll cover both IBL and Final Gather in depth in Chapter 11
when you light the decorative box model and apply displacement maps for its details.
mental ray Physical Sun and Sky
An impressive function in mental ray for Maya has been the implementation of a Physical
Sun and Sky lighting methodology. In this method, mental ray for Maya creates nodes in
your scene to simulate an open-air sunlight effect for your scene lighting. It's a quick way
to create a nice-looking render. You'll place the textured red wagon into
an open scene and apply a Physical Sun and Sky (PSAS) in the following
exercise.
You can use your own scene with the textured red wagon from
Chapter 6, or set your project to the RedWagon project and then load
WagonSunlight_v01.ma
from the Lighting project on the CD to follow along.
Keep in mind that if you use your own scene, your camera angles and look
won't be an exact match to the igures in the topic. Follow these steps:
1. The camera for this scene is already set up for a somewhat interesting angle of the
wagon in the persp panel. Switch to mental ray rendering in the Render Using pull-
down menu at the top of the Render Settings window, as shown in Figure 10.39.
2. Open the Render Settings, and click the Indirect Lighting tab. In the Environment
heading, click the Create button next to Physical Sun and Sky. The Attribute Editor
opens for the mia_physicalsky1 node you just created, as shown in Figure 10.40.
Figure 10.39
Enable mental ray
rendering in Render
Settings.
