Tasks in your project plan may feed into overarching parent tasks. That is, child tasks one and two may compose parent task three. For instance, developing a product plan could be an overall track of work, composed of child tasks to define business requirements, compose a launch schedule, and define use cases. Children and parent tasks are similar to, but not the same as task dependencies. While parent tasks do depend on child tasks, those child tasks roll up to the parent. The parent work track is generally not a task itself.
For instance, in the Gantt view below, we can see that our "Product Use Case Definition" task and our "Business Requirements" task are children of our "Product Plan" parent. Parent taskbars bracket the child tasks beneath them and inherit attributes like end dates from their child tasks.
Creating task hierarchies
You can create tasks hierarchies for Gantt charts the same way you create row hierarchies. To indent tasks in a row and make one task child to another task, select the indent rows button in the toolbar and that row will become the child of the one above it. Or reverse this with the outdent rows button in the toolbar. You can pick any cell in a row and the entire row will indent or outdent to the row above it.
Indenting a row makes a collapse icon appear in the parent cell that is in the primary column. In the animation below, we make "Business Requirements" a child task to "Product Use Case Definition". Not only does this show up as indenting in our sheet, but it changes the start and end dates for our parent task.
Parent cell rollups
Parent tasks are not treated as tasks themselves. Instead, they inherit the attributes of the child tasks beneath them. This is why, in the animation above, the dates for our "Product Use Case Definition" task changed when we made it a parent task.
These "rollups" happen in Spreadsheet.com by default and make particular cells in parent rows uneditable. However, you can also use unique parent cell formula to reference child cells. For instance, you might wish a parent row to inherit each of the owners from its child tasks.
The full set of hierarchy functions includes: