Years ago, before Max's advanced lighting and mental ray reached the scene, global illumination was simulated through the careful placement and adjustment of standard lighting. It was more an art than a science. Now, with advanced renderers and photometric lighting, global illumination has become more a science than an art. You will learn that in global illumination there are numerous ways to achieve a satisfying result, perhaps as many ways as there are those who use it.
This tutorial was created with Max 7 using mental ray version 3.3. I can only guarantee comparable results for those using the same versions of this software. Use of other packages will most likely lead to differing results.
Let's get busy....
Step 1: Setting Up Our Directory
For this tutorial you will only need to download file, Global_Room.rar. All the needed geometry and mapping are included in this file. Once you've downloaded it to your PC, create a new directory in the Scene directory of Max and label it Global_Rooms.
Into this newly created directory you will want to uncompress the needed files.
Download the Global Room file here.
There are four Max files in Global_Rooms, one called Small_Room.max and the other Global_RoomMR.max, each with a finished version. We'll start with Small_Room.max, which will give you a chance to see how easy it is to create global illumination in a very simple room.
Open Small_Room.max and take a few moments to study the simplicity of the scene. Your first view will be of an average sized room, 168 inches by 168 inches by 96 inches, in smooth and wire frame view. The single light source is a Photometric Free Point light positioned to act like a typical ceiling light. Hit the C key to view the room through the camera, then F9 for a quick render. The default scanline render shows us a very dark room; the green sphere in the corner is barely visible. Photometric lights are designed to be used by either Max's advanced lighting or mental ray's Indirect Illumination. Now, let's switch our renderer to mental ray and enable Global Illumination before we try the render again. Close the Render window. Hit F10 to open the Render Scene panel, click the Common tab and slide all the way down to the bottom. Open the Assign Renderer rollout, and click the button to the right of Production: Default Scanline Renderer to open the Choose Renderer panel, double click mental ray Renderer
If you were to render right now, you'd find the rendered image still dark, so let's enable Global Illumination. While we have our Render Scene panel available, click the Indirect Illumination tab, then click the Enable option box in the Global Illumination area. Leave all the other settings to their defaults for now. Now, click the Render button at the bottom of the panel. Your render should look like this: