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S-02 How Sheetshift AI works

Sheetshift AI, step by step.

One real run, from the Gardner River High Bridge case study: bid plans against amendment 1. For each step: what went in, what the code did, what Sheetshift AI did, the real numbers, and one real crop.

  1. 01Set Check

    Done by: Code

    What went in
    The old and the new drawing set, as PDFs.
    What the code did
    Counts the lines, words and pictures on every page, calls each page a drawing, a drawing made of pictures, a scan or a written page, and finds the title box. Written pages are set aside and never compared.
    What Sheetshift AI did
    Nothing yet. This step only measures.

    71

    pages in Bid plans

    74

    pages in Amendment 1

    7

    drawing sheets in Amendment 1

    67

    pages that are notices, specification pages or reports, left out of matching

    Amendment 1 holds 74 pages; 67 are written pages, not sheets, so they are set aside and never compared.

  2. 02Sheet Match

    Done by: Code and Sheetshift AI

    What went in
    The title box of every sheet.
    What the code did
    Reads the sheet number from the title box as text where it can, then pairs by number, then by title, then by how alike the pictures are. A sheet with no partner is listed.
    What Sheetshift AI did
    Sheetshift AI reads the title box picture to get the sheet number when it is drawn as lines. A pair that depends on a picture alone waits for a person to confirm it.

    7

    sheets paired

    7

    paired by the printed sheet number

    0

    paired by title box reading or picture

    64

    old sheets Amendment 1 did not re-issue

    D.3, oldD.3, new

    D.3 — title needs confirmation

    Paired by the sheet number

    F.3, oldF.3, new

    F.3 — title needs confirmation

    Paired by the sheet number

    S.2, oldS.2, new

    S.2 — General Notesfrom the drawing index

    Paired by the sheet number

    S.4, oldS.4, new

    S.4 — Approach Span Sectionsfrom the drawing index

    Paired by the sheet number

    D.3 to D.3, F.3 to F.3, S.2 to S.2, S.4 to S.4, S.5 to S.5, S.6 to S.6, S.7 to S.7

  3. 03Lining up

    Done by: Code

    What went in
    Each pair of sheets.
    What the code did
    Tries no shift, the longest lines, and a picture match, and keeps the best. If part of a sheet will not line up, it says so instead of guessing.
    What Sheetshift AI did
    Nothing. Lining up is measured, not read.

    0

    pairs that needed a shift

    0

    areas listed as not checked

    Every pair already sat on the new sheet with no shift.

  4. 04Cloud Check

    Done by: Code and Sheetshift AI

    What went in
    The new sheet's lines and a small picture of it.
    What the code did
    Finds the wavy outlines and the numbered triangles on the new sheet, and measures how much of each change sits inside a cloud: inside, partly inside, or not marked.
    What Sheetshift AI did
    Confirms each cloud on a small picture of the sheet and reads each tag's number.

    13

    clouds found

    13

    confirmed by Sheetshift AI

    0

    with nothing found inside

    9

    changes inside a cloud

    10

    partly inside

    12

    design changes outside every cloud found

    Old version of C-049
    Old · C-049
    New version of C-049
    New · C-049

    C-049 on S.4: inside a cloud.

  5. 05Change Finder

    Done by: Code

    What went in
    Both sheets in the same coordinates.
    What the code did
    Compares every line, shape and word in the same coordinates, drops the tiny differences that come from plotting, and groups the rest into changes a person can read.
    What Sheetshift AI did
    Nothing in this step.

    7612

    tiny plotting differences dropped

    98

    differences grouped by the engine

    46

    changes in the final list

    Old version of C-049
    Old · C-049
    New version of C-049
    New · C-049

    C-001: note

  6. 06Change Notes

    Done by: Sheetshift AI

    What went in
    The before and after crops of the changes found.
    What the code did
    Sends the before and after crops of each change, one request for each sheet, and keeps a copy of each answer. Every number, size and label in a note must appear in the change's old or new words, or the note is written again once. If it still fails, the sheet's own words are shown instead.
    What Sheetshift AI did
    Names each change, reads the old and new values, writes the note, says how sure it is of the values and whether everything inside the change is explained, and sets aside changes that are only drawing noise.

    45

    notes that passed the value check first time

    1

    rewritten, then passed

    0

    shown as the sheet's own words

    49

    Sheetshift AI calls

    $0.44

    AI cost of the whole run

    Old version of C-049
    Old · C-049
    New version of C-049
    New · C-049
    C-049Wording or number changedMedium
    Design changeInside a cloud

    Values: SureCoverage: Complete

    The stirrup bar mark changed from #4B5 to #4B4 under revision 1.

    Old
    #4B5 Stirrup (typ.)
    New
    #4B4 Stirrup (typ.)
    • bar mark: #4B5 Stirrup → #4B4 Stirrup
    • stirrup bar mark: #4B5 Stirrup (typ.) → #4B4 Stirrup (typ.)
    • revision triangle: nothing → 1

    May affect Reinforcement: The stirrup bar mark changed from #4B5 to #4B4.

    Re-check: Check the bar bending schedules and order lists for the correct stirrup mark.

    Sheetshift AI suggests. Needs an engineer's confirmation.

    C-049: The stirrup bar mark changed from #4B5 to #4B4 under revision 1.

  7. 08Check First

    Done by: Code and Sheetshift AI

    What went in
    The changes found, their type and their cloud status.
    What the code did
    Orders the list with each change's type and cloud status in mind. Nothing is deleted: probable noise is set aside, not removed.
    What Sheetshift AI did
    Ranks each change High, Medium or Low and says why.

    7

    changes ranked Check first

    47

    set aside as probably not a design change

    Old version of C-061
    Old · C-061
    New version of C-061
    New · C-061
    C-061Wording or number changedHigh
    Design changeNot marked

    Values: Fairly sureCoverage: Complete

    Bar marks #6S8 and #6S16 were changed to #4S8 and #4S16 respectively, with revision 1 tags added.

    Old
    #6S8 and #6S16
    New
    #4S8 and #4S16
    • bar mark #6S8: #6S8 → #4S8
    • bar mark #6S16: #6S16 → #4S16
    The table as it was and as it is now. Changed cells are highlighted.
    #4S84140'-2"Guard Angle
    (header)#6S8#4S8····
    #4S16#4S164140'-2"Guard Angle
    #6S16#6S16removed4removed14removed0'-2"removedGuard Angleremoved

    May affect Reinforcement: Bar marks changed in the schedule

    Re-check: Re-check bar schedule and procurement list for #4S8 and #4S16

    Sheetshift AI suggests. Needs an engineer's confirmation.

    C-042: Adds detailed scope of work descriptions and quantities for structural repairs.

  8. 09Team Routing

    Done by: Code and Sheetshift AI

    What went in
    The changes found and the project's teams.
    What the code did
    Matches each change to the project's own teams. A person accepts or changes every suggestion.
    What Sheetshift AI did
    Suggests which team should look at each change and gives the reason.

    20

    changes with a suggested team

    9

    Formwork team

    8

    Concrete and rebar subcontractor

    3

    Steel fabricator

    C-010 is suggested to Formwork team: This change is in the formwork and temporary works package and shows construction limits.

  9. 10Issue Brief

    Done by: Code and Sheetshift AI

    What went in
    All of the above.
    What the code did
    Puts the whole revision into one short page: what to check first, what nobody marked, and what the designers' own list leaves out.
    What Sheetshift AI did
    Writes the headline and the lines under each heading, from the change list only.

    7

    lines under Check first

    4

    lines about changes nobody marked

    ChangeWhat changed
    C-049The stirrup bar mark changed from #4B5 to #4B4 under revision 1.Inside a cloudMedium
    C-061Bar marks #6S8 and #6S16 were changed to #4S8 and #4S16 respectively, with revision 1 tags added.Not markedHigh
    C-042The general notes list was expanded from 6 notes to 10 notes, adding detailed descriptions for repairs, rivets, and quantities.Inside a cloudHigh
    C-056The bar size changed from #4S13 to #4S7.Inside a cloudHigh

    Amendment 1 introduces 46 real changes across 7 sheets, with bar callouts and general notes requiring immediate review.

All numbers are from one real run of the Gardner River High Bridge drawings. The case study page lists where the run fell short.

S-13 Start

Check your next revision before your team builds it.

Upload the old and the new set. The first comparison is free, up to 30 sheet pairs.

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Questions? Write to hello@sheetshift.ai