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Global Illumination in 3DS MAX

Global illumination (GI) in 3DS MAX

Picture 1. GI in 3D Studio MAX.

21.06.2007 Category: 3D (Lighting)
Too often 3D models are rendered without a proper lighting. Lighting has a very big influence on how the final image will look like. In this tutorial I cover the use of simple global illumination in 3D Studio MAX.

Global illumination means lighting model which takes into account the bouncing of light from surfaces. As a result objects receive indirect illumination and the rendering will be more realistic. GI is commonly used acronym for Global Illumination.

Default Rendering in 3DS MAX

Default rendering in 3D Studio MAX

Picture 2. A rendering with 3D Studio MAX 9 default settings before any lights have been created. (If the user doesn't create lights, 3DS MAX illuminates the model with two invisible omni lights.)

Picture 2 has been rendered using 3D Studio MAX 9 default settings before any lights have been created. There is a white plane object under the characters. None of the objects have a material. They all have just a color. The rendering is boring and not very realistic. Additionally the color difference between the background and the plane divide the picture disturbingly into two parts. Let's illuminate the model using global illumination and blend the plane to the background.

You can do the same exercise with any model. Create a white plane object under your model. The plane object should be big enough for the shadows below the characters.


Create a Skylight (Create > Lights > Skylight). The position and orientation of the Skylight don't matter at all. In any case the Skylight will illuminate all around from top. Open the Light Tracer settings (Rendering > Advanced Lighting > Light Tracer...) and try to render the model. The rendering is already more realistic but rather dark.

By default Skylight has a light blue color which makes the rendering look little cold. You could change that for example to pure white. If you want to blend the plane into the background use white color in the plane, background and skylight.

Light Tracer

Light tracer settings for global illumination

Picture 3. Light tracer has many settings but only few are needed in basic cases.

Light tracer rendering with skylight in 3ds max

Picture 4. A rendering using a skylight and simple global illumination lighting in 3D Studio MAX. Even a simple model can look nice when it's properly illuminated and rendered.

By default settings Light Tracer doesn't calculate the bouncing of the light. Set Bounces to 2 so that the light falls also on the second surface after the first bounce. The whole model will be brighter. It's usually enough to use 2 as Bounces value. Larger value always means slower rendering and for example the difference between values 2 and 3 is very small.

Light Tracer has many settings but in simple cases you don't need many of them. As a rule of thumb: If there is graininess in the shadows and you want better quality raise the Rays/Sample value.