What-ifs and comparisons

Scenarios are overlays, not copies

A scenario records only your changes — durations tweaked, tasks added, links rewired — applied over the live baseline at view time. The baseline itself is never touched: you can pile up a dozen what-ifs, delete them all, and nothing happened. Because overlays are small, scenarios are cheap to create and cheap to throw away, which is exactly how what-ifs should feel.

Comparing

Open two branches side by side and Foreweave shows, for each: the finish date, the delta between them, and — the part spreadsheets can't do — which tasks enter or leave the critical path between the two. "The second test lab takes certification off the path" is an argument that writes itself.

Scenarios can also carry their own duration-uncertainty estimates, so you can simulate each branch and compare P80s, not just deterministic dates — see your first simulation.

Promoting

When a what-if wins the argument, Promote applies its changes to the baseline in one atomic operation, recorded in the audit history. The scenario's changes become the plan; other scenarios remain as overlays on the new baseline and report any overrides that no longer apply.