As I said before, Ambient occlussion pass is a “must” in realistic renders.
When you composite your “beauty render” with ambient occ., reflection occ etc. It will give you a chance to change their values in compositing so you can control your project well..
Let’s do it;
Firstly, in the menu, select [Windows] > [Rendering Editors] and select [Hypershade]
If it is written “Create Maya Nodes” under “Create” tab on left, change it to “Create All Nodes”, If you dont change that, we can’t see mental ray shade nodes.
Select “Surface Shader” under “Surface” section,
Go to “Textures” section and click “mib_amb_occlusion”
When you click shader buttons, it will add them into Work Area.
Mouse middle click and hold on “mib_amb_occlussion” in Work Area and drag on to SurfaceShader1, when you realase your button you will see a menu,
Select “Other…” from the menu,
You will see “Connection Editor” dialog box,
Firstly, from left side, select “outValue” and then from right side, select “outColor”
Press Close, now you have a ambient occlusion shader
Close HyperShade window and press [ChannelBox / Layer Editor button] (CTRL+A opens and changes Attibute Editor and Channel Box)
You will see a layer editor in below, it writes Display Render Anim.. , check “Render” circle
Right click and hold on masterLayer (normal) > Overrides > Assaign Existing Material Override and you will see your surfaceShader in the menu, select it.
And render it with mental ray,
To change its settings, open hypershade again, hold on SurfaceShader with right click and select “Graph Network”
Double click “mib_amb_occlusion” in Work Area and you will see its settings in Attribute Editor
Increasing “samples” value will increase your render time but will give better results.
When you render your Ambient Occlusion pass, you can turn your scene shader back to old.
To turn it back, in the Channel Box / Layer editor, right click hold on masterLayer (normal) > Overrides > Remove Material Override
That’s all folks,
Keep in Fx,