Constraints

Location on ribbon: Tab DVD Cons → Group Schedule → Menu Setup

Command ID: btnConstraints

PRO feature

This command is part of the PRO package. STANDARD accounts activated before 1 July 2026 keep access until their licence expires; other Standard accounts will see an upgrade dialog.

What it does

Applies Primavera P6 / MS Project style date constraints to the task rows you select: MSO (Must Start On), SNET (Start No Earlier Than), FNLT (Finish No Later Than) and Deadline (a soft deadline).

Use it whenever the schedule cannot float freely with the network: contractual milestones, site-handover dates, the day the tower crane arrives, phase-completion deadlines. The add-in writes the constraint into two sheet columns and recalculates so dates and violation flags update immediately.

How to use

1. Open the schedule sheet and select at least one task row inside the data area. If nothing is selected, the add-in tells you: "Select at least one task row (in the data area) before setting a constraint."
2. Go to the DVD Cons tab → Schedule group → Setup menu → click Constraints.
3. The Set task constraint window opens with:
   • Type — choose MSO / SNET / FNLT / Deadline.
   • Date — the constraint date.
   • A Clear constraint from selected rows checkbox — use it to remove constraints instead of setting them.
4. Click Apply (or Cancel). Missing type or date is flagged inline in the window.
5. The add-in creates the Constraint Type and Constraint Date columns if the sheet lacks them, writes the values into the selected rows, then recalculates. A message reports how many tasks were updated.
6. Read the constraint cell colour: green = met, red = conflict / late (hover for details).

Example

The contract requires Level 1 fit-out for the opening to finish by 30 November, while Tower crane erection cannot start before 5 September because the site is not handed over until then.

Select the Tower crane erection row → Constraints → Type SNET, Date 05/09 → Apply: the start date is pushed to 5 September and the downstream chain shifts with it. Now select Level 1 fit-out → Type FNLT, Date 30/11 → Apply: the cell turns red because the current schedule finishes on 8 December, telling you that you need to compress by eight days.

Notes

• You must select rows first — with no task row selected inside the data area the command just shows a message and stops.
• The active sheet must be a valid schedule worksheet; otherwise the add-in warns and changes nothing.
• You can also type straight into the Constraint Type / Constraint Date columns (a dropdown is provided); with Auto Calc on, the schedule refreshes live.
• MSO and SNET are hard constraints — they actually move dates; FNLT and Deadline are flagging constraints — they colour the cell red but do not compress the task for you.
• Writing the columns and recalculating cannot be undone with Ctrl+Z; to remove a constraint, rerun the command with the Clear constraint checkbox ticked.

Related

• Auto Calc — turn on so hand-typed constraints take effect immediately.
• Gantt Chart — redraw the chart after the constraints have moved the dates.
• Update Status — check Δ Finish against the milestones you just pinned.
• Schedule Recovery — when an FNLT turns red, build a recovery plan.