When doing a Release Planning with a team, it's not always the case that we have all User Stories ready. Most of the time, we only have the Epics and in the initial Release Planning, we size the Epics. We breakdown the Epics that we think should be tackled first and estimate work that is good for at least 3 sprints. We then work on refining the remaining epics and fleshing out the user stories in Backlog refinement sessions.
Will I still be able to generate a Release Burndown chart (not Epic burndown) even with only Epics sized? How does the Release burndown calculate when both the Epic and its stories are sized/estimated?