In addition to the timeline which reuse Jira Issue hierarchies, from the version 1.4.47 Cloud and 7.0.0 for Server/Data Center we support the WBS Gantt, it maintains a custom hierarchy and provides advanced Gantt feature such as Critical Path, Baseline, Milestone
Initiate WBS Gantt
By default the WBS Gantt is enabled by default, when it is accessed for the first time the current hierarchy in Timeline will be copied and assigned the Work-Breakdown-Structure (WBS) number accordingly. The changes afterward will be maintain in the WBS order and not synced with Jira Issue hierarchy TImeline. WBS Gantt can be disabled by Jira admin or the board admin.
Go to Board Settings → Features
You can select to enable which feature on the board, Timeline and WBS Gantt both can be available together but to avoid confusion we recommend using only 1 on your board.
WBS Gantt features
Menu
Work on Gantt
Drag & drop to change location and hierarchy
Create new issue with hierarchy
Quickly create new Issue with its hierarchy
Manage progress
Slide on the bar to edit the progress
or edit it in the Issues table
Board admin can configure the Progress field in Board settings
Critical path
Click on the Critical Path button to show the critical path
Baseline
Gantt baseline is a snapshot of the current positions of tasks and milestones in the Gantt timeline, which can be placed alongside the chart at a future date. You can use the baseline to compare the current state of Gantt with the state at the time the baseline created
Create a baseline
Click on the Baseline and select New baseline then enter the name and create
Enable baseline
Click Baseline and find the baseline you want to enable and select it
When a baseline is enabled you can confirm the baseline bars on the Gantt timeline
In the screenshot the gray thinner bars are the baselines, you can customize the color in board settings.
Deselect the baseline to disable it