mental ray Shader connections

 
 
 

The following mental ray shader parameter types are recognized as message attribute by Maya: light, geometry, color texture, scalar texture, vector texture, lightprofile, shader.

Though it is possible to connect any node to these attributes, you should make only those connections that Maya expects, otherwise a crash or rendering abort may occur. That is, if you drag a node to the message attribute in the Attribute editor, the message attribute of the source node will be connected to the attribute (for example node1.message > mrShaderNode.shader), but only the following connections are recognized and will work in Maya: