How to use Hierarchy and Child extension.

[slimshader]

1. It seems it is completely separate from Child extension, does that mean that if I want to have tree-like structures with parent-child lifetime management AND processing in the order of HierarchyLevel I have to use both extensions?

2. How to use ParentSystem or HierarchyLevelSetter? They are both internal and there is no API documentation for extenions.

[Doraku]

Stuff in the Extension project are just example of what can be built on top of the basic api to add more features. As said in the readme:

A DefaultEcs.Extension project is present to show how other features can be built upon the base framework. Those features are just provided as example and are not part of DefaultEcs because the implementation is not generic nor satisfactory enough.

So you can copy them into your own code and modify it as needed. It should be easy enough to integrated the Children feature in the Hierarchy one automatically when you set the parent for example.