---
title: "Generate a schedule proposal"
description: "The Optimize pill on the scheduler Gantt computes a constraint-aware plan and draws it as dashed indigo ghost bars with a banner reading violations and span before and after. Nothing is written until you click Apply, which saves every included move as one undoable batch. Completed, locked and in-progress work is pinned and never moves, and a scoped run on a selection holds the rest of the board fixed and plans the selection around it. Clicking a ghost skips that move, so you can apply part of a proposal."
category: "Schedule work"
source_url: "https://www.iotflows.com/docs/production/optimize-the-schedule/"
---
# Generate a schedule proposal

Let IoTFlows compute a constraint-aware plan from the work already on the board, then review it before any of it is written.

Resequencing a busy week by hand means holding dependencies, machine availability, shift hours and tool contention in your head at once. The optimizer does that arithmetic and hands you the answer as a preview.

It writes nothing on its own. You get a set of proposed bars and a banner of numbers, and you decide whether the numbers are worth the moves.

**Before you start**

- Production Scheduler is part of the Scheduling Engine module. The tab strip renders for every organization, so seeing the **Scheduler** tab is not proof you are entitled to it. If you are not sure, [contact IoTFlows](/docs/get-started/get-support/).
- You need edit access to the board. See [Give people access to a scheduler board](/docs/production/scheduler-members/).
- The work needs **Time Estimate** values. A task without one is planned as an hour, which is rarely right. See [Create a production work order](/docs/production/create-a-job/).
- Optimize runs on the Gantt. See [Plan jobs on the scheduler board](/docs/production/scheduler/#gantt).

## What Optimize does
A *proposal* is a computed plan the board shows you but has not saved. The optimizer walks your work orders in dependency order, earliest due date first, and gives each one the earliest slot where its machine, its materials and its predecessors all allow it.

It only ever changes two things on a work order: the due date and the **Time Estimate**. Quantities, statuses, assignees, dependencies and the machine stay exactly as they are.

**Put real Time Estimates on the work before you judge the optimizer.** A task with no estimate is drawn as a one-hour bar carrying a `~1h` chip, and the plan is only as good as the durations it is given. A board where most bars read `~1h` produces a thin proposal, and that is the most common cause of a disappointing first run.

## Run it on the whole board
With nothing selected, click **Optimize** in the Gantt toolbar. The proposal appears immediately, since it is computed in your browser.

![A cropped detail of the left half of the Gantt toolbar. Four pills read Sequence, Working hours, Work sessions and Optimize, the last carrying a sparkle icon and ringed in violet, with undo, redo and download icons past a divider to its right.](/images/production/prod-opt-01.webp)

*The Optimize pill in the Gantt toolbar, after Sequence, Working hours and Work sessions. It plans against the Time Estimate on each task, so a task without one is planned as an hour.*

**Run it on a selection first.** A whole-board run on a busy schedule moves work people have already promised to customers, and the fastest way to lose trust in the optimizer is to apply one of those. [Optimize only what you selected](#scoped) is the safer first run.

> **Info:**
> **Should Working hours be on?** Turn it on before you optimize if the plan has to stay inside shifts. The optimizer reads the same toggle the bars do: with **Working hours** off it plans straight through nights and weekends, and the proposal will be shorter than anything the floor can deliver. See [Turn on Working hours](/docs/production/scheduler/#working-hours).

Optimize is unavailable in Sequence view, because those bars stand for order rather than time and carry no time axis to move along.

## Review the proposal
Every move is drawn as a dashed indigo ghost bar at the proposed time, joined to its live bar by a dotted line, with a chip above it reading how far it shifts: `6h later`, `1.2d earlier`, or `gets scheduled` for a task that had no date.

![The Gantt with a proposal on screen. An indigo banner reads Optimized proposal: span 66.9d to 15.2d, 54 moves, 3 scheduled from No date, with Recompute, Apply 54 moves and a cross at its right end. Below it six lanes of the DMG DMU 65 group each hold a narrow live bar toward the right of the chart, and well to the left of each sits a dashed indigo ghost bar joined to it by a dotted horizontal line, with a chip above reading 3.1d earlier, 8.8d earlier, 11.4d earlier or 9.4d earlier. A violet arrow runs from the top lane's live bar back to its ghost.](/images/production/prod-opt-02.webp)

*An optimizer proposal on the Gantt. Each move it suggests is drawn as a dashed indigo ghost bar, joined to the live bar by a dotted line, and nothing is written until you apply.*

**You do not need to accept the whole proposal.** Click a ghost to skip that one move: it turns gray, takes a `skipped` label, and **Apply** relabels itself `Apply 12 of 18`. Click it again to put the move back.

Skipping is how you protect a job you have already promised without losing the rest of the plan. To protect it permanently, right-click the bar and choose **Lock scheduling** instead, which takes it out of every future run.

## Read the banner
*Span* is the stretch from the earliest start to the latest finish across the board's scheduled work, written as `66.9d`. Lower is better.

The banner above the chart is one sentence of numbers followed by the three actions. It reads, in order: violations before and after, span before and after, the number of moves, and the number of tasks scheduled from **No date**. Violations only appear when the board has at least one before or after, so a permanent `0 to 0` never sits there.

![An indigo banner across the top of the Gantt carrying a sparkle icon, with four numbered callouts in the board header immediately beneath it. Callout 1 marks the sentence, which reads Optimized proposal: violations 5 to 4, span 66.9d to 15.2d, 54 moves, 3 scheduled from No date. Callout 2 marks a Recompute button with a refresh icon, callout 3 a filled indigo button reading Apply 54 moves, and callout 4 a small cross at the right end.](/images/production/prod-opt-03.webp)

*The proposal banner: one line reading violations and span before and after with the number of moves, then Recompute, Apply and the cross that discards.*

**If span barely moves and violations do not fall, discard it.** Eighteen moves that buy half a day are eighteen conversations you now owe the floor, and a proposal that gains nothing is telling you the schedule was not the problem.

The banner does not report double-booked machines. To see that number change, check the issues pill before and after, or run the optimizer inside a [Simulation](/docs/production/simulate-a-schedule/#optimize), whose band carries **Double-booked** as its own metric.

### Proposal actions
| Action | Effect | Undoable |
|---|---|---|
| Click a ghost bar | Skips that move and dims the ghost. **Apply** relabels to `Apply 12 of 18` | Nothing is written yet |
| **Apply N moves** | Writes a due date and a **Time Estimate** to every included work order | Yes, as one step |
| **Recompute** | Discards this proposal and runs the optimizer again over the same scope | Nothing is written |
| The cross at the right end | Discards the proposal and leaves the board as it was | Nothing is written |
| Clicking **Optimize** again | Same as the cross | Nothing is written |
| Regrouping the board | Clears the proposal | Nothing is written |

## Apply the proposal
**Apply** saves every move you did not skip. Each work order is written on its own, and the whole set lands in the undo history as a single entry, so one **Undo** puts the schedule back where it was. A run of more than one work order confirms with **Apply optimized schedule · 18 work orders**.

> **Warning:**
> **What does Apply write to a task with no estimate?** The one-hour default. A `~1h` bar that moves comes back with a real **Time Estimate** of 60 minutes, which then looks like a number somebody chose. Set the estimates you know before you apply, not after.

If some of those writes fail you get **4 of 18 updates failed, reverted**: the four that failed go back to the dates they had, the rest are saved, and the proposal closes either way. Run it again for the ones that did not take.

Inside a Simulation, **Apply** stages the moves instead of writing them, so they join the draft and wait for Commit. See [Run the optimizer inside a Simulation](/docs/production/simulate-a-schedule/#optimize).

## Recompute
A proposal goes stale the moment one of the work orders in it changes underneath you, whether you dragged the bar, edited it in the drawer, or a colleague moved it. The banner replaces its numbers with **The schedule changed while previewing. Recompute to get a fresh proposal.** and **Apply** is disabled until you do.

![A cropped detail of the indigo proposal banner. Where the sentence of numbers was, it reads The schedule changed while previewing. Recompute to get a fresh proposal. The Recompute button is ringed in violet and the Apply button to its right is dimmed.](/images/production/prod-opt-05.webp)

*When a work order in the proposal changes, the banner replaces its numbers with a line saying the schedule changed, and Apply is disabled until you recompute.*

Only the due date, machine and duration of a work order the proposal moves are watched. Editing a title, or a bar the proposal left alone, does not flip the banner.

**Recompute** reruns the optimizer over the same scope the proposal started with, so a scoped run stays scoped. Any ghosts you had skipped come back included.

## Discard
Click the cross at the right end of the banner to throw the proposal away. Clicking **Optimize** again does the same thing, and so does regrouping the board. Nothing was written, so there is nothing to put back.

## Optimize only what you selected
A *scoped run* is a run that may move only the work orders you selected. Select bars first, by dragging a box across the chart, **Shift**-clicking to add, or holding **Ctrl** and clicking one bar to take its whole dependency chain. The pill then reads **Optimize 5 selected**.

![A cropped detail of the Gantt toolbar with bars selected on the board below. The Optimize pill, ringed in violet, has widened to read Optimize 5 selected. To its left sit Sequence and Working hours unfilled and Work sessions filled blue, and to its right the undo, redo and download icons.](/images/production/prod-opt-04.webp)

*With bars selected, the pill reads Optimize 5 selected. A scoped run may move only those five work orders and plans them around everything else.*

Everything outside the selection is held exactly where it is. It still reserves its machine time and its materials first, so the selection is planned *around* the untouched work rather than on top of it, and an unselected predecessor still sets the floor for a selected successor.

The banner names the scope: **Optimized 5 selected:**, then the same numbers. Press **Esc** to clear the selection when you are done.

Select a rush order and its chain, run it, read the span, and you have asked "how early can this finish without disturbing anything else" and got an answer in one gesture.

## What it will not move
*Pinned* work keeps its dates and its machine and is reserved before anything else is placed. Three things are pinned, always: work that is **Completed**, work that is **In Progress**, and work you locked with **Lock scheduling** on the bar's right-click menu. A locked bar carries a padlock and cannot be dragged by hand either.

Select only pinned work and there is nothing to plan. The board says so rather than opening an empty banner: **Nothing to optimize in the selection: those work orders are completed, locked or in progress.**

A run that finds no improvement is also a valid answer, not a failure. The banner opens reading `0 moves` with **Apply** disabled, which means the optimizer could not beat the plan you already have.

## What it respects
### What Optimize respects and what it pins
| Input | Treated as | Notes |
|---|---|---|
| Completed, in-progress and locked work | Pinned | Reserved first, then planned around |
| Everything outside the selection, on a scoped run | Pinned | Same treatment as completed work, for that run only |
| Dependencies | Hard constraint | A task starts no earlier than its predecessor finishes, pinned predecessors included |
| One job at a time per machine | Hard constraint | Keyed to the machine on the work order, so the answer is the same in every grouping |
| Working hours | Respected when **Working hours** is on | Off, the plan runs through nights and weekends |
| Setup time on the work order | Added before the task starts | Arrives from your ERP import or the API; no dashboard field sets it |
| A serialized piece or a reusable tool | Capacity constraint | Work waits for the piece or the tool to come free. See [the capacity lane](/docs/production/scheduler/#capacity) |
| Demand larger than the shop owns | Placed anyway | No amount of moving fixes it, so it stays flagged as a violation |
| Now | Floor | Nothing is planned into the past, so overdue work all comes forward |
| The machine on the task | Untouched | The optimizer plans each task on the machine it already has |
| A task with no due date | Pulled in when it has a machine | It gets a date and the banner counts it under `scheduled from No date` |

Tasks with no due date and no machine stay in the unscheduled chips down the left of the board. Give one a machine, or drag it onto a date yourself, and the next run will plan it. See [Schedule work that has no dates](/docs/production/scheduler/#unscheduled).

## See also
- [Try a schedule change without saving it](/docs/production/simulate-a-schedule/)
- [Find and fix problems in the schedule](/docs/production/schedule-issues/)
- [Plan jobs on the scheduler board](/docs/production/scheduler/)
- [Create a production work order](/docs/production/create-a-job/)