Instances are useful for duplicating geometry by referencing an original copy to save memory and time when processing and rendering many objects. These instances can then be shaded differently to create interesting and realistic variations without overloading the artist or the computer with many unique copies.

Copy to Points SOP

Create a Copy to Points SOP and wire geometry to be instanced into the first input, and positions to instance to in the second input. 

Instance OBJ

Create an Instance OBJ as you would normally create Houdini instances. 

In the Instance node, set your Instance object and select Fast point instancing or Full point instancing. Currently these two options result in the same behavior in the renderer.

To override material for the instanced objects, we can use the Material SOP inside the Instance.