CPM Planner — Construction Scheduling Software

1What this system does

CPM Planner is construction scheduling software of the same kind used on government projects and large private-sector jobs. It runs in the browser — no installation required.

2CPM in 2 minutes

If you are not yet familiar with the CPM method, read this paragraph first — the rest of the manual will be much easier to follow.

• The whole project is broken down into activities, each with a duration in working days.
• Activities are chained together by relationships — for example, the footings must be poured before the columns can go up.
• The system runs a forward pass to find the early start (ES) and early finish (EF), then a backward pass to find the LS and LF.
• The difference between the late start and the early start is the Total Float — how long that activity can slip without delaying project completion.
• Activities with Float ≤ 0 are critical activities, linked together into the critical path — a 1-day delay on any of them immediately delays project completion by 1 day.

3Permissions and data saving

Who can do what

Where data is stored

• Auto-saved on every edit — to the browser on the device you are using; no need to press a save button · If you want to be sure before closing the page, press Save on the toolbar (or Ctrl+S) and the system writes to the device and sends to your account immediately without waiting
• Synced to your account — if you sign in with an account that has edit rights, the plan is also sent to your account; sign in on another device and you see the same plan
• The status chip on the toolbar briefly shows Synced (green dot) · Syncing… (blinking yellow dot) · Auto-saved · This device only (not signed in) · Sync failed (orange) · Not saved (red) — hover over or click the chip to read the full message; clicking also makes the system retry sending to your account
  • Could not load data from the account — not synced means the account data could not be read; the system will not touch the data on either side until it can be read
  • Could not save to this device — storage is full means the browser is full; export your work, then clear old website data first
• Both sides merged, nothing overwritten — when the page opens, the system compares the plans on the device and on the account project by project; the one edited later wins, and projects that exist on only one side are both kept, so work not yet synced to the account is never overwritten by older data
• Automatic local backups — before every overwrite of a plan, the system keeps the 3 most recent backups · Restore them at Project settings → Restore plan from local backup; the plan on the device at that moment is always backed up once more before restoring

Confirmation pop-ups before deleting or overwriting

Every button that makes data disappear or be replaced always shows an “Are you sure you want to…” pop-up first. The pop-up states the item name, number and the actual quantity that will be lost — read it before pressing · If you press by mistake, in most cases pressing Undo on the toolbar (or Ctrl+Z) fixes it immediately, except Restore from backup, which has to be restored again (see Toolbar)

Buttons that ask first:

• Delete — project · work group (WBS) · activity · crew · relationship (✕ in the details panel) · holiday · rain day · start-date constraint
• Clear or replace the whole project (backed up automatically) — clear all activities · reset to sample data · import JSON · import CSV · restore from backup
• Baseline — set the current plan as the baseline (states how many activities have durations different from the previous baseline) · reset activities to the baseline

The file you choose to import is read first, so the pop-up can tell you how many activities the file contains and which project it will replace

4Tour of all 10 menu pages

The top bar of every page has summary chips for Critical activity count · the project Finish date, and the Run CPM button · below that bar is the toolbar

Toolbar (on every page)

The second row under the page header, the same set as in BOQ Studio · the left side shows the last save time and how many steps can be undone

5Create a new project

On the All projects page, scroll down to the Create a new project box and choose a template. The system immediately creates the starting work groups, activities and relationships for you

Sample projects

The first time you open the program there are 4 sample projects (road–bridge · 8-storey building · warehouse · 2-storey house) with progress, baselines and EVM figures you can read right away · The sample sets use the same structure as the templates: a WBS 3–4 levels deep, each group header followed by that group's activities, with milestones inside their own groups · If you deleted them and want them back, press the Add sample projects button on the All projects page (it adds only the sets you don't have yet)

Each project card shows the status (Starting · Under construction · Near handover · Handed over · On hold), progress, budget, actual cost and amount billed · Press Open this project to switch to working on that project

Receiving a plan from BOQ Studio

In BOQ Studio, on the BOQ by system page → By work group (WBS), press the Send to CPM button, choose the activity level, budget and duration estimate, and this page opens with the Receive plan from BOQ Studio window (if CPM is already open in another tab, the window also appears in that tab)

Planning with your own AI (attach a PDF → CPM plan)

The AI planning menu lets the AI you already use — Claude · ChatGPT · Gemini or any program that supports MCP — read the construction drawings and lay out the plan for you: WBS groups (up to 5 levels deep), activities, durations (working days), crews, manpower, budgets, milestones and FS/SS/FF/SF relationships + lag · AI usage costs are charged to your own AI account · the plan does not enter the project until you review it and press import

• The pre-import review window — number of groups, activities, milestones, relationships, estimated duration, total budget · notes/assumptions from the AI · what the system corrected · a group tree with activities, durations, crews and budgets
• Import as — Create as a new project (recommended · code AI-xxx · start date from the plan → the one you entered → today) or Replace plan in open project (project data, calendars and crews stay as they are) · The system backs up the plan before every import and you can press Undo · after import, the Schedule & Gantt page opens with start–finish dates, critical activities and Float based on the actual calendars
• The system always checks the plan first — creates missing parent groups · activities referring to non-existent groups are moved to the parent group · durations are rounded to whole days · milestones are 0 days · crews with non-matching codes are guessed from the activity name · budgets sent in THB are converted to million THB · removes relationships that are duplicates, point to themselves, refer to non-existent activities or create loops — every item is reported in the review window
• AI without MCP support (e.g. Gemini on the web) — switch to No MCP — paste JSON, copy the prompt to use it, then paste the whole answer back (it may contain text or ```json blocks) and press Check plan · works without signing in

Connecting SketchUp / Revit (model → plan → 4D)

The Chang Pile plugin reads the elements in the model (storeys · work groups · volume/area/length) and sends them to CPM Studio for automatic planning — WBS groups by storey, activities, durations from quantities, crews and relationships · every activity is linked to elements in the model, so the schedule can be sent back to color the model by status on a chosen date and play 4D week by week · card B is in the AI planning menu

Installation	How to
Revit 2025 · 2026 · 2027	Download ChangPile-BOQ-CPM-v2.0.0.zip → extract → close Revit and double-click Setup.exe → Install (it finds the Revit / SketchUp versions on the computer by itself) → open Revit and press Always Load · The buttons are on the Chang Pile → CPM Studio (4D) tab · to install manually without Setup: install.cmd in the zip file · IT teams can build the installer from source with plugins/build.ps1
SketchUp 2017 or later	Download changpile_cpm.rbz → in SketchUp Extensions → Extension Manager → Install Extension → choose the file (or use the Setup.exe above) · the Chang Pile BOQ & CPM toolbar (icons ) or the Extensions → Chang Pile BOQ & CPM menu
MCP link (optional)	Use the same personal link as step 1 on this page — enter it in the MCP link settings menu (SketchUp) or Settings (Revit) · it also works without a link, by saving/opening a .json file instead

• Rules for planning from the model — preliminaries → piles → footings → beams-slabs → columns, working up one storey at a time · walls/stairs start 3 days after the columns (SS) · masonry starts 7 days after the next floor slab is complete · doors-windows → ceilings → finishes · MEP follows masonry · roof after the topmost structure · system testing → handover
• Durations from quantities — e.g. footings 8 m³/day · beams-slabs 8 m³/day · columns 3 m³/day · masonry 25 m²/day · piles 4 piles/day (per crew) · rounded to 2–60 days — you can adjust them on the schedule page to suit your actual crews
• BOQ take-off from the same model — the Chang Pile BOQ & CPM plugin has a Send model for BOQ take-off menu/button that sends element types and sizes to BOQ Studio (RC members · doors-windows · walls, plaster, paint · ceilings · surface finishes · roofs · structural steel); see the BOQ Studio manual
• Privacy — the plugin sends only quantity summaries and element IDs, never the model file or geometry · coloring uses Override Graphics (Revit) / temporary materials (SketchUp) and never modifies the actual elements

6Project settings and calendars

Finish this step before entering activities, because the calendars and the project start date affect the dates of every activity

1. Enter the contract information

   Project name · project code · contract number · scope of work · project owner · location · project status · budget · amount billed · reporting week

   This information appears on all report headers and weekly reports — enter it once and use it throughout

2. Set the project start date

   This is the starting point of the forward pass — change it and the system immediately recalculates the schedule for the whole project

3. Set the Data Date (cut-off date)

   The date used to cut off progress, usually set to the Friday at the end of the reporting week · this value drives both the EVM calculation and the midpoint of the 3-week look-ahead plan

4. Set up the work calendars

   The system has two ready-made calendars: Civil works calendar Mon–Sat and Office calendar Mon–Fri · click a weekday to toggle it between working day and day off, and each activity can use a different calendar

5. Enter holidays and rain days

   Enter public holidays for the whole year in advance · Rain days are a key feature for construction in Thailand — turn on the option to deduct rain days from working days and the plan will reflect the actual rainy season

7Build the WBS and activities

Go to WBS & activities — this page is the heart of the system; every cell in the table can be edited directly

Work sequence

1. Add work groups

   Press + Add WBS group and name the group, e.g. Preliminaries · Structural works · Architectural works · MEP works

2. Break out sub-groups (if needed)

   Press + Sub-WBS in the group header bar; you can go up to 5 levels deep, e.g. Structural works → Superstructure → Main structure → Floors 1–4 (see the next topic)

3. Add activities to a group

   Press + Activity in the header bar of the group you want. The new activity is always appended after that group's activities (before its sub-groups) and gets the next code after the previous row, e.g. after A2110 comes A2111, and the system links an FS from the previous activity in the group for you, so the new work starts after the existing work instead of on the first day of the project · The + button at the end of an activity row = insert a new activity after that one and link an FS for you · The system selects the new row, scrolls to it and opens the name cell for typing right away — it works the same way as the + button on the Schedule & Gantt page

4. Add milestones

   Press ◆ Milestone in the group header bar or ◆ Add milestone at the top for zero-duration milestones such as “Structure topped out at roof level” or “Project handover” · A milestone has a duration of 0 days · The top button places it after the currently selected activity in the same group and links an FS from that activity for you (if no activity is selected, it goes to the end of the last main group)

5. Choose a calendar for each activity

   Site work uses the civil works calendar Mon–Sat, while paperwork/permit activities use the office calendar Mon–Fri

6. Enter resources and budgets

   Fill in crew · persons/day · budget (THB) so the manpower chart and S-Curve have data to calculate

Multi-level WBS (1–5 levels deep)

The group code shows its level — 2 = level 1 · 2.1 = level 2 · 2.1.3 = level 3 … up to 2.1.3.1.2 = level 5 · An activity can belong to a group at any level; choose it in the activity's WBS group cell (the list is indented by level so you can see the hierarchy)

Every page displays by level — Schedule & Gantt and printed documents are indented by level with a summary bar for each group (main groups have their own colors, sub-groups use the same color as their parent, and the colors on screen and in print match) · The Value by WBS group table on the S-Curve & EVM page shows every group at every level with branch totals

WBS depth arrows — check that work is in the right place

Available on the WBS & activities page and in the group list on the Project settings page · the Schedule & Gantt page and printed documents show the hierarchy by indentation only, to keep them easy to read and clean

Every arrow uses the color of its main group · Hover over an arrow or the WBS group cell to see the full group path, e.g. “A2200 is at level 4 · 2 Structural works › 2.2 Superstructure works › 2.2.1 Main RC structure › 2.2.1.1 Structure, floors 1–4” — use it to check that work sits in the right group before setting the baseline

Understanding the table columns

Adding and deleting activities on the Schedule & Gantt page

No need to switch to the WBS & activities page — keep planning right on the chart

After adding, the system selects the new row, scrolls to it and opens the name cell for typing right away; the default duration is 10 days — edit it in the Days cell or choose a finish date · these buttons do not appear in printed documents · if the Critical only filter is on, the system turns it off first so you can see the new activity · if you press by mistake, Undo (Ctrl+Z) always works

Collapsing–expanding groups and choosing which groups to show

Plans with dozens of WBS groups can show only the part you are interested in, on both the Schedule & Gantt page and the WBS & activities page — this does not touch the project data (CPM still calculates every activity and the project finish date does not change) · Each page remembers its own view, e.g. collapse groups on the management page to fill them in one part at a time while the Gantt page still shows everything

• The ▾ / ▸ button before the group code — click it on a group row to collapse it (hiding the activities and sub-groups of the whole branch) or expand it again · Gantt page: a collapsed group still shows its summary bar for the period, with a ▸ N activities collapsed label at the end of the bar · management page: the button is at the far left of the group row and the activity count reads ▸ Collapsed · total N activities (the + Activity · + Sub-WBS · Delete group buttons of the group row still work)
• The “All WBS shown ▾” drop-down on the toolbar of both pages (on the management page it sits before the “WBS depth” box) (the label changes to “6/20 WBS shown · 2 collapsed” while filtering, and the button turns orange)
  • Collapse / expand WBS — Expand all · Collapse all (level 1) leaves only the main groups · To level 2 … 5 shows groups down to the chosen level
  • WBS shown — a list of groups at every level in structure order, with activity counts · click to show/hide · the Only button (hover over the row) = show only that group and its parent branch · Show all · Hide all · ▾/▸ in the list collapse–expand just like in the table
  • Reset — shows and expands every group
• The system remembers the view per project on the device, so it is the same when you reopen it · it works together with the Critical only filter · press + Activity in a collapsed/hidden group and the system opens that group so you can see the new activity
• Relationship lines with one end hidden are not drawn · Preview & print A4/A3 prints according to the Gantt page's view — use it to produce documents per group or a summary of the main groups only for management · you can still drag to reorder groups/activities on the management page as usual while some groups are collapsed

Scrolling through long, wide tables

The table on the WBS & activities page has many columns and may have hundreds of WBS rows, so the system helps as follows

• Scroll bars always on screen — the table fits the screen height, you scroll up–down inside the table, and the left–right scroll bar sits under the visible part of the table, so there is no need to scroll the page to the very bottom first · column headers stay pinned at the top
• ID and activity name cells pinned on the left — even when you scroll to fill in the last columns (calendar, crew, budget), you can still see which row you are filling in
• Group rows — the group label is pinned on the left, and the + Sub-WBS · + Activity · ◆ Milestone · Delete group buttons are pinned on the right, so you can press them at any time
• The “Scroll table” button on the bar above the table — to the top · bottom · far left · far right in one click
• Floating scroll bar at the bottom of the screen — for any wide table whose bottom edge is still below the screen (e.g. Schedule & Gantt on a short screen), a left–right scroll bar as wide as the table floats at the bottom of the screen; you can drag it right away, with ⤒ ⤓ ⇤ ⇥ buttons to go to the top/bottom/first column/last column · once you scroll down far enough to see the table's real scroll bar, the floating bar disappears by itself
• Regular mouse: hold Shift and turn the wheel = scroll left–right

Widening columns to see all the data

Activity or group names so long they are cut off with “…” can be revealed by widening the column, Excel-style, in the Schedule & Gantt · WBS & activities tables · Value by WBS group (S-Curve & EVM page) · Resources and cost per activity (Resources page)

• Drag the right edge of a column header — the line turns orange when you hover; drag to widen or narrow it, and the table grows as you drag · in the Gantt, the table pane on the left widens and the chart, Data Date line and relationship lines shift accordingly
• Double-click the edge — the column widens to fit the longest text in that column
• Reset columns — this button appears on that table once you have dragged; press it to return to the default widths
• Widths are remembered in this device's browser per table and survive a reload · they are display settings for each device, not synced to your account, and do not affect project data

8Relationships and constraints

Click the Start or Finish cell of any activity to open the details panel on the right

The 4 relationship types

Lag and Lead

The right-hand box of each relationship is the Lag (working days) — a waiting period, e.g. waiting 7 days for the concrete to cure before stripping the formwork · enter a negative value to make it a Lead, so the next activity starts before the preceding one finishes

Date constraints

The Constraint (start on or after) field forces this activity not to start before the specified date, e.g. waiting for a permit or for site handover · if it is not set, the system lets the dates follow the relationships alone, which is the recommended setting

The What-if panel

Below the relationships panel is a Project impact box that tells you plainly:

• If this activity is on the critical path — adding 1 day to its duration immediately delays project completion by 1 day
• If it is not on the critical path — how many days of Total Float and Free Float remain, and how far it can slip or stretch at most

9Baselines and progress updates

Setting the baseline

Once the plan is stable and approved, press Set as baseline (available on both the WBS & activities page and the Project settings page) and the system copies all dates and durations and keeps them as BL1

Weekly progress updates

1. Move the Data Date

   In Project settings, set the Data Date to that week's cut-off date

2. Enter actual progress

   Enter the Physical % Complete of activities in progress, or edit the Remaining Duration to match what actually remains, and the other cell adjusts accordingly

3. Enter the rain days that actually occurred

   Add past rain days on the settings page so the plan explains delays by their true cause

4. Press Run CPM

   The system recalculates and highlights the critical path as it has changed

5. Check at-risk activities

   On the Project overview page, look at the “At-risk activities” card, sorted by lowest Total Float

10Reading the dashboard and EVM

Top-row KPIs

The S-Curve and its three lines

• PV (plan) — cumulative value of work that should have been done according to the plan
• EV (earned) — cumulative value of work actually completed
• AC (actual) — cumulative cost actually paid, including labor and materials

Put simply: EV below PV = work is behind plan and AC above EV = spending more than the work earned

Other dashboard cards

• Critical path — the sequence of activities that controls the finish date
• Progress — plan vs actual — compared group by group with the variance
• Value by WBS group (S-Curve & EVM page) — budget, PV, EV, AC, SPI and CPI for every group at every level, sorted by group code and indented by level · a parent group's totals include all sub-groups in its branch, while the Total row is calculated from the actual activities so nothing is counted twice
• Key milestones — milestones with their status: completed / due / how many days late
• At-risk activities — sorted by lowest Total Float, used to decide which work to accelerate first
• Monthly manpower — the peak persons/day in each month, used to plan labor procurement
• Estimate at completion (EAC) — forecast of the total cost at project completion based on the current spending rate

11Look-ahead and weekly report

The 3-week plan

The 3-week look-ahead page places the Data Date in the middle and pulls the activities out into 3 columns

Each activity has a status tag in the right corner of its card — Critical is work on the critical path · Continuing is work that started before that week · Starting is work that has just started that week

These two tags usually appear in the last-week column — Completed (green chip) means 100% done, while Overdue (red chip) means work that has passed its finish date but is not yet complete — these items are what you should put on the meeting table first

Print it to hand out at the weekly site meeting, to review past work and let subcontractors know in advance what workers, materials and equipment they need to prepare

The weekly progress report

The Weekly report page is formatted specifically for sending to the project owner and contains

• A header with the reporting week and the cut-off date
• Work carried out this week and the plan for next week
• Issues affecting the critical path
• Problems, obstacles and solutions (the text can be edited)

Press Preview to see the page before printing

12Import–export and printing

Project file (JSON)

• Export project (JSON) — back up the whole project or move it to another device · you can also use the Export JSON button on the toolbar of every page
• Import project (JSON) — must be a file exported from this system only · if the file contains circular relationships, the system refuses the import · files from earlier versions that put the group headers at the very top are automatically rearranged so activities sit under their groups

Activity table (CSV)

• Export activity table (CSV) — open it in Excel to build comparison tables or send it to other departments · there is also an Export CSV button on the toolbar
• Import activity table (CSV) — the file must have at least an Activity column and a Duration column
• The WBS column is written as group code · group name, e.g. 2.1.1 · Earth retaining system and piles, and there are WBS group path (names of all parent groups in the branch) and Milestone columns — export and import back and you get the WBS hierarchy, group names and milestones exactly as before · for files whose WBS cell contains only the group name (files from earlier versions or made by hand in Excel), the system puts activities with the same group name in the same group · activities without a code or with a duplicate code are given codes by the system according to their position

The safest method is to export a CSV from this system first to use as a template, then edit that file before importing it back

Printing the Gantt and documents

On the Schedule & Gantt page, press Preview & print A4/A3 and choose

• Paper size A4 or A3 (A3 suits projects with many activities)
• Orientation landscape or portrait — the Gantt should use landscape

The page header pulls the company name, taxpayer ID number, phone number, logo and preparer's name from the user profile — set it once and it works for every document

Adjusting column widths on paper

In the Schedule & Gantt document preview, you can drag the edges of the ID · Activity · Days · Start · Finish · TF · % column headers just like the on-screen table, so activity names are not cut off in the document

• The paper width is fixed — however much wider the left table gets, the chart on the right gets that much narrower · drag on any page and every page changes together; relationship lines and the Data Date line follow
• The system keeps the left table no narrower than 30 mm and leaves the chart at least 25% of the paper width, for A4/A3 in landscape/portrait
• Double-click the edge = fit the longest text · the Reset columns button appears on the bar at the top of the preview once you have dragged
• Widths are stored in millimeters, so the printed PDF matches the preview · they are remembered on this device separately from the on-screen table

The summary bars for each group in the document use the same group colors as the on-screen Schedule & Gantt page

13Recommended weekly routine

This sequence takes about 20–30 minutes a week and keeps the plan from going out of date

14Frequently asked questions

15Glossary of system terms