Drawing compare: Measurement & quantities (TSA)

Open this screen in Saral/projects/drawing-compare?view=scope

The Measurement & quantities tab of Drawing compare: the project's Tender Sum Analysis (TSA), kept as revisions. The drawings folder, the rates workbook and the base TSA are saved once for the project. The drawings in the folder are measured once, in the background, and kept: a drawing that has not changed is never measured twice. One button, Generate measurement & pricing, takes the measured drawings, fills blank rates from the rates workbook and writes a new draft revision. The draft opens as the TSA itself, with the previous quantity struck through on every changed line, a record of what happened to each file, a short list of what needs checking, and the measured drawings to review. An issued revision is never changed. Download any revision as an Excel workbook with working formulas.

You enter

The SharePoint link to the drawings folder, once, and optionally one zone
The link to the project's rates workbook, once
Optionally the project's TSA workbook (.xlsx), to build on its layout and agreed rates
The wall height of a level, when Saral asks for it: where the drawings give none, or only one it cannot be sure of
Which changes to keep or put back, and who prepared and authorised the revision you issue

Saral fills in

What is in the folder as soon as you paste the link: how many files, DWG and PDF
The wall height of each level where a section or a schedule gives it, with where it was found; a level with none is marked Wall height needed, and one it cannot be sure of is marked Confirm
A draft revision: quantities measured off the plans and matched to the TSA's lines, or the whole workbook built from the drawings when there is no base TSA
Blank rates from the rates workbook, only on a line with a quantity and no rate; a line with no match is shown as no rate
What happened: one row per file, read, skipped or failed, with the reason and the TSA lines it fed
Needs checking: estimates read off a scanned PDF, quantities that move a lot, lines with no rate, measured items with no line
The General Summary: each summary group, sub-total, OH&P and total, in the revision's own currency

It produces

A new draft TSA revision each time you press Generate; the revision it was built on is not changed
The TSA as an Excel workbook with working formulas: cover, control issue sheet, contents, General Summary, one sheet per trade, and, when there is an earlier revision, previous quantity and amount columns plus a Changes sheet
An issued revision, with who prepared and authorised it, when you press Issue revision

The order to work this tab

1 Where to read from: the drawings folder, the rates workbook and the base TSA, saved once for the project, then press Generate measurement & pricing → 2 The result: the draft as the TSA itself, with What happened and Needs checking → 3 Check the measured drawings under Review drawings → Issue revision and Download TSA at the top right. The same numbers are on the tab's cards.

What is not automatic

Generate never changes an issued revision: it always writes a new draft, and a draft is not issued until you press Issue revision. A quantity read off a scanned PDF, or one that moves a lot, is held under Needs checking until you press Apply it. A rate already on a line is never changed, and a line with no match in the rates workbook shows no rate, never zero. Saral never guesses a wall height: it looks on the drawings first, and where it finds none, or only one it cannot be sure of, the wall area waits until you type or confirm the height and press Generate again. Openings are not deducted from wall areas. Under Other ways to update, nothing is applied until you tick it and press Apply.

Revision 0 is your workbook

Importing the TSA workbook makes revision 0: its sheets, items, quantities, rates and OH&P exactly as you priced them. Every later revision is built from the one before it, when someone presses Generate or applies proposals, and earlier revisions are never changed. A base TSA is optional: with none, Generate builds the workbook from the drawings.

Reading the drawings folder

Saral reads the folder in place through your group's SharePoint connection; nothing is copied or stored. It goes through every sub-folder except ones named _SS (superseded revisions), reads only the latest revision of each drawing number, and keeps to the zone you typed (plus drawings for all zones) if you typed one. PDF and Excel schedules and DXF or IFC drawings are read, and DWG and PDF plans are measured. Each sheet is measured off one file: its DWG when the folder has it (the PDF of the same revision is drawn behind the pieces when the two line up), otherwise its PDF. A PDF printed from CAD has real lines but no layers, so its quantities are medium confidence at most; a scanned PDF is read by recognising its text and tracing its lines, so its quantities are estimates: they are held under Needs checking and are not in the draft until you press Apply it. What happened says what each file was measured off. Four kinds of plan are also measured by their type tags, and the levels are added together into one proposal per type: a screed plan and a ceiling plan (the area each tag such as 1c or C1b encloses), a floor finishes plan (the floor each finish such as ST-01 names), and a drylining plan (the run of each wall type such as IL1, in metres). A wall is priced by area, and the height is not on a plan, so Saral looks for each level's height on the drawings in the folder and lists it under Wall heights. A height read off a section or a schedule is used as it is. A height that is only floor to floor (level datums), a ceiling height, or another level's is marked Confirm and the wall areas using it are held; a level with no trace of a height is marked Wall height needed and gets no wall area. Type or confirm the height and press Generate again. The run is never dropped: the metres of each wall type waiting are listed. Openings are not deducted. A floor finish is matched to a line only when its code is on exactly one line of the finishes sheet in square metres; otherwise it comes as a new line for you to place. These are proposals to check, not finished measures. Each one names every plan, counts any tag it could not measure, and is never marked high confidence, and See what was measured opens a picture of exactly what was measured, with anything left out of the quantity (floor with no finish name, a stud with no type tag) in grey. On a screed or ceiling plan an enclosed space with no tag is left blank and counted in the notes with its total area, never added to a type. The scores so far come from one project, one architect's drawing standard, against the surveyors' hand take-off of one townhouse. Floor finishes: the total was within 1 per cent on a level not used to write the rules, and 6 of 7 finishes were within 5 per cent. Ceilings: level totals and large types were within about 3 per cent, but small rooms and window strips can be 10 to 30 per cent out. Walls: runs read 4 to 8 per cent short in total, about half the types were within 10 per cent, and openings are not deducted. Screed: the whole-building total was within about 2 per cent, but single types were 10 to 15 per cent out either way, and tags it could not enclose are listed. Check the measured drawing before you issue. Revit files are not read. What happened lists every file it read, skipped or could not read, with the reason. A large folder is not cut short: every drawing is measured once in the background and kept against its file version, so only new drawings and new revisions are measured after that, and Generate itself reads nothing from the folder again.

From a CAI's accepted changes

Accept the drawing changes on the CAI review tab first. Propose then matches each accepted change to the TSA lines it touches: the line's quantity plus the change where the units agree, a new line for an item the TSA does not have yet, and a low-confidence "re-measure" proposal where Saral can see the line is affected but cannot work out the quantity. A revision applied this way is labelled with the CAI's reference.

Proposals and applying them

Each proposal shows the sheet, item, location, current and proposed quantity, the change, its source (schedule, CAD, measured, or estimate — check), its confidence and its evidence. Select all high-confidence ticks the strong ones; an estimate is never ticked for you. Apply N selected writes the next revision. Quantities and units change and evidence is added, but a rate is never touched: a rate is your price. A new line has no rate until you add one. A line whose quantity you set by hand is changed only when you tick its proposal, and the revision records the quantity before and after.

The workbook you download

Download TSA builds the Excel on your computer from the revision on screen, with working formulas: each amount is quantity times rate, each sheet ends with a sub-total, the General Summary adds the sheets up, and OH&P is an input you can change. Quantities that are estimates are tinted and marked "Estimate — check". When the revision has an earlier one, every trade sheet gets Prev Qty, Prev Amount and Change columns and a Changes sheet lists every line added, removed or changed.

Who can do what

Anyone who can view project reports can open Measurement & quantities, look at every revision and download the workbook. Saving the drawings folder link, pressing Generate, keeping or putting back a change, importing a workbook, proposing from a CAI or from measurements, applying proposals and issuing a revision need permission to manage the project's commercials. Linking the rates workbook needs permission to manage Projects settings.

From measurements

On a drawing, measure with the measure tool and give the measurement a TSA line: the sheet and the item code (leave the code blank to propose a new line). Publish it. From measurements then sums every published measurement tagged to a line and proposes its quantity, worked out again from the points and the page scale each time. A measurement on a page with no scale, or on a drawing that has gone, is counted and named, never added as zero.

Issue a revision

A revision is saved as a draft. Issue revision marks it as issued, with who prepared and authorised it and the issue date, and adds a row to its Control Issue Sheet. The revision issued before it becomes superseded. Only a draft can be issued.

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