The checkpoint device serves as a routing aid in the workview . The contents of each connection are passed through from the input to the corresponding output without modification.
This can be useful for organizing your workspace and keeping a set of necessary wires together. You can also assign a custom name to each channel as an organizational aid.
Checkpoint Memory Conservation
In the Artist Point version and beyond, the Checkpoint device have gained a new ability.
When building a high resolution world, you can choose to use “Checkpoint memory conservation” in the project settings. This lets checkpoints function as a kind of results caching system, keeping high resolution build results only at each checkpoint instead of at each device. This saves enormous amounts of memory while still allowing you to edit and rebuild the world from the last checkpoint.
In the example above, the devices retains the terrain and erosion masks, allowing you to tweak the quick texture settings with a minimum of rebuild time and memory usage.
How to Use
Make sure in your Project Settings you have enabled checkpoint memory conservation:
Then add a checkpoint to your world. When the world is built, the devices that input into the checkpoint will be conserved and their results removed, while the checkpoint will retain all of its data.
Typically, each major section of your world file that you may want to edit would route all of its output through a checkpoint to minimize the amount of the world that must be rebuild on a change.
Note that the checkpoint only caches data at buildtime, it does not save data to disk if the world is saved and then loaded.