Geo-Channel Node

Access: Nodes > Geometry > Geo-Channel

The Geo-Channel system allows you to use the same material on a variety of models to achieve the look of edge wear and tear and other photo-realistic effects on your meshes. You might not know what geometries will be used when authoring a material. Geo-Channels solve this by driving geometry-agnostic data, such as curvature and ambient occlusion maps into your material setup. The Geo-Channel node points the material at specifically set up Geo-Channels on your object.

Material without Geo-Channel node.

Material with Geo-Channel node driving a curvature map to show edge wear in the material.

You can use the Geo-Channel node anywhere in the Node Graph by making sure Geo-Channels have been setup for your object under the Geo-Channel Properties in the Objects palette. See Adding Geo-Channels to Objects for more information.

Tip:  You can also export baked data from Bake Point nodes directly into Geo-Channels, to act as an intermediate caching point for complex Node Graph setups that can then be added to your Node Graph through a Geo-Channel node. See the Bake Point Node and Working with Nodes for more information.

Geo-Channel Node Properties

Channels

Dropdown

Select the Geo-Channel alias from the dropdown box to be used by the Geo-Channel node.

Background Color

swatch

Fills any UDIMS on the geometry not included in the Geo-Channel with the selected color. For example, if your geometry has UDIMS 1001-1003 but your Geo-Channel only has 1001-1002, 1003 is filled with the selected background color.

Assigning a Geo-Channel to a Geo-Channel Node

Note:  Make sure you have Geo-Channels setup on your object. See Adding Geo-Channels to Objects for more information.

1.   Press tab, type 'Geo-Channel' and select the resulting Geo-Channel node.
2.   Double click the Geo-Channel node in the Node Graph to bring up the node properties.

3.   Click the Channels dropdown and click the geo-channel you want to use with this Geo-Channel node.

The Geo-Channel node updates visually with a blue icon and channel name to represent the Geo-Channel you selected.

Without a geo-channel selected.

With a geo-channel (Curvature) selected.

Importing Materials with Geo-Channels into New Projects

When you import a material containing a Geo-Channel into a new project, if the Geo-Channel is missing from the object(s) in your project, double-clicking the material in the node graph displays a warning in the node properties. The missing Geo-Channels are displayed in the Missing Geo-Channel(s) panel.

Tip:  Click the Geo-Channel layer in the Layers Palette to open the Geo-Channel properties when working with layers instead of the Node Graph.

Tip:  See Working with Materials in the Node Graph for more information on exporting and importing materials.

To add the missing Geo-Channel:

1.   Click Geo-Channel Properties.

This opens the Geo-Channel Properties tab.

2.   See Adding Geo-Channels to Objects for information on how to add a Geo-Channel to the object.

Note:  Make sure the geo-channel name matches the geo-channel selected in the Geo-Channel node.

Geo-Channel Node Workflow Example

Creating Edge Wear and Tear Using Geo-Channels

Geo-channels can be used in a material pipeline to create realistic wear and tear such as rust, chipped paint, or worn leather on your objects. Since geo-channels are geometry-agnostic, you can use the same material across a variety of objects while ensuring the material looks realistic for the specific object. The Geo-Channel node is most useful when used as a mask on the object.

In the video:

What are Geo-Channels?

How are Geo-Channels useful to you?

You learn how to add Geo-Channel properties in the Object Palette.

You learn how to add a Geo-Channel node to your material setup.

You learn how to export your material setup to be used in other Mari projects.

You learn how to importing your materials to other Mari projects and how to deal with missing Geo-Channels.

Related Nodes

Ambient Occlusion Node

Bake Point Node

Curvature Node

Grade Node

Invert Node