Site or project administrators can create hierarchical relationships between projects so that one project can inherit members, roles and permissions from a parent project.
When you define users, user groups and roles with specific permissions in one project, they can be inherited in one or more subprojects. This helps you avoid duplicating the effort of defining users, user groups and roles across projects.
You can still, if required, create roles specifically for this project and add direct members to any project. The direct members can be assigned inherited roles. The inherited members can be made direct members and/or assigned direct/inherited roles too.
While inheriting roles, only the permissions associated with all (top-level) folders are inherited.
In a subproject, you can select the inherited project members from the Assigned to lists or from the user picker, as the case may be. Inherited users may not be part of these lists if their role inheritance was prevented in the parent project.