Applying changes to a (nested) prefab takes a very long time.
Nested Prefabs has to check every (nested) prefab for modifications, it does this by gathering all properties in the entire nested prefab and comparing them to the original prefab. If the prefab contains components with an unusually large amount of properties then it can slow down the Nested Prefabs plugin. A few of the common components that can cause a slowdown are:
- A large amount of particle systems. Each particle system contains a few hundred properties, compared to an average of 10-20 properties for most components. Having a lot of nested particle systems can cause a slow apply time.
- ProBuilder objects. Unfortunately, ProBuilder saves its mesh data as an array of serialized properties, resulting in thousands of saved properties in a prefab. This can slow down Nested Prefabs to a crawl, and it is recommended to not directly nest any ProBuilder objects for now. One way to use ProBuilder with nested prefabs is to export the ProBuilder mesh as an '.obj' file and use the exported mesh instead of the ProBuilder object. As of Nested Prefabs version 1.3.3 and higher, ProBuilder objects no longer slow down the plugin as much and can be nested directly, instead of exporting them.
- General performance issues can cause slow apply times. Read this article to troubleshoot slow performance.