Reference/Release Notes/2.80/Depsgraph

= Blender 2.80: Dependency Graph =

The core object evaluation and computation system in Blender has been rewritten. This was done to improve performance, particularly on modern CPUs with many cores.

Objects, modifiers and constraints are now updated in parallel more often, which improves performance in scenes with many objects and complex rigs. Driver evaluation has been updated to support multithreading in many cases, by avoiding Python for simple expressions. For some complex scenes running on CPUs with many cores, all these changes can give an order of magnitude better performance.

It also makes it possible to create more flexible driver and constraint setups, without creating dependency cycles. We also expect to add new features in future releases that are only possible with this new system:
 * New override system
 * Multithreaded export of scenes to renderers
 * Animation playback while editing in another window

The new dependency graph uses more memory than before, to support a clearer separation the original edited data, and evaluated data with modifiers. In practice for production scenes the increase is often moderate, as other sources of memory usage dominate.