Render nodes are the individual components you interconnect to use as building blocks to produce all rendering effects. Like all other nodes in Maya, you can animate or map render nodes to other nodes’ parameters. For more information on Maya nodes in general, see Nodes and attributes overview.
Texture nodes, placement nodes, and material nodes along with their input and output connections (attributes) define all aspects of the final rendered images, from surfaces to lights and shadows.
You can connect nodes to create the effects you want. You can also share nodes to create visual relationships, and to make rendering more efficient. For example, two objects can share a single texture so that both objects appear the same, but less memory and, or processing is required.
You can see and work with rendering nodes and shading networks in the Hypershade window.