Introduction

Ambient occlusion adds great realism to your renders, but can be bit cumbersome to set up in Max, particular if you're using a mix of mental ray shaders and standard shaders. You could create an ambient occlusion effect by using lights, but it can be slow to render and tricky to get the right look. So if you want to skip all that, you can simply use a material override in your render options to get the job done – it's super fast and gives you the added bonus of having the ambient occlusion in a separate pass. As a separate pass you can adjust and manipulate to your heart's desire without affecting the rest of your render.

Please note that this tutorial uses 3ds Max 2011 and Photoshop CS5. Earlier versions should work too, but there might be slight differences in interface.

Step 1: Create a mental ray material

First you have to make sure you have assigned mental ray in your Render Setup menu (press F10) (Fig.02).




Then open your Material Editor (press M) and select an empty material slot. Give it a new name, like "AO material” and click the Standard button to select the mental ray shader in the Material/Map Browser (Fig.03).


You should now see the mental ray shader. Under Basic Shaders click the Surface parameter and select Ambient/Reflective Occlusion in the Material/Map Browser (Fig.04).