Q100502: Using Materials in the layer stack

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SUMMARY

This article will cover the unified stack rules when using the Multi-Channel Layers, why we have implemented them and what are their benefits. The unified stack rules are not relevant to Mari versions prior to 4.5v1 and are not applicable for Node Graph workflow.


MORE INFORMATION

The unified stack is a layer system for the material multi-channels. The unified stack is also referred to as the Multi-Channel Layer. This material layer spans across multiple channels which are connected to a defined shader input. We have introduced the unified stack and a set of rules for the user to follow in Mari 4.5v1.

The unified stack presents restrictions of how the channels that contain material layers can be used. This set of rules protects the project data from becoming corrupt over time. The rules implemented are the following: 

  • Channels containing Multi-Channel Layers should be connected to a Shader of the same Shader Model (BRDF, Unreal, Arnold Standard Surface etc.).

  • Channels containing Multi-Channel Layers can be connected to multiple shaders with unique shader models but cannot be connected to multiple similar shaders. For example a Base Color channel can be connected to Principled BRDF and a BRDF shader models but it cannot be connected to two Principled BRDF shaders. Connecting the channel to multiple similar Shader will result in the following error:

  • A channel containing a Multi-Channel Layer cannot be connected to multiple inputs of the same shader. For example the Base Color channel cannot be connected to both the Base Color and Specular input in the same shader. Connecting the channel to multiple inputs will result in the following error:

 

  • Merging Multi-Channel Layers is not supported as they first need to be converted to Paintable layers. If the user tries to merge two Multi-Channel Layers this will result in the following error:

 

  • Duplicating a shader which has channel inputs containing Multi-Channel Layers is not allowed and it will result in the following error:

  • The Multi-Channel Layers can be grouped using the Multi-Channel Group layer. Attempting to group the Multi-Channel Layers using a standard Group layer will result in the following error:


This set of rules simplifies the layer stack workflow, making it less possible for the user to accidentally break their layer stack, scene, shader or textures.

These restrictions only apply if the user wants to use Materials or Multi-Channel Group layers. If these features are not used, the user can still use Mari same as in the versions prior to 4.5v1.

 

FURTHER READING

For further details on the unified stack rules, please visit the following documentation:  Multi-Channel Layer Workflow Rules