Create Object Buffers using Material Override in Cinema 4D

By January 1, 2018 October 23rd, 2018 3D Modeling, Animation, Tutorials

Have you ever rendered out your final animation only to realize you forgot to enable the object buffer pass? Before Cinema 4D R17, you would have had to change all the object materials in your scene to pure black, disable all lights, then set the objects that you want as a matte to pure white. With R17 and above, it’s very easy to create object buffers with the new Material Override system.

Define Your Object Buffers

The first thing to do is define which objects in your scene will be the object buffers. These will be rendered as pure white. There are two ways to do this.

Option 1: Use a White Material

The first option is to create a new material and enable only the Luminance channel and set its color to pure white:

White Material

This would then be applied as an excluded material in the Material Override settings:

Material Override

This white material would then be applied to all the objects in your scene that you would want as buffers:

Object Manager with Object Buffers

Option 2: Use a Compositing Tag

The slightly cleaner method is just to assign a Compositing tag to each of your buffer objects. Then on the tags properties, you enable Matte Object, and set its color white:

Compositing Tag Object Buffers

Enable Material Override

The next thing to do is just enable Material Override. But before we do that, we need to provide Cinema a material to override all objects in our scene. This needs to be a pure black material. Create a new material and only enable the Luminance channel and set its color to black:

Black Material

Open the Render Settings and enable Material Override. Then drag the black material to the Custom Material slot. We don’t want the other materials in our scene to preserve Transparency, Bump, Normal or Alpha, so go ahead and uncheck these:

Material Override Settings

In case you have objects in your scene that need Displacement, you can leave this enabled. You can also turn off Ambient Occlusion, or any other special render effects you might have enabled. You shouldn’t need to worry about disabling any lights in your scene, since only setting our black color in the Luminance channel basically ignores receiving lights, shadows, reflections, etc. If you’ve got depth of field or motion blur in your scene, you can leave these enabled.

That’s it! The rest is pretty much up to you. Set your desired frame range, save as a PNG sequence without alpha, etc. It should render very quickly, since Cinema doesn’t have to worry about calculating reflections, transparency, etc. For any questions or concerns, please use the comments section below.

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