Drawing reader

Metric drawings come back ballooned and in inches. Anything doubtful gets flagged first.

A small tool your quality team opens in a browser. Upload a part drawing and it reads every callout, puts a numbered balloon on each one, converts the metric sizes and tolerances to inches, and fills in the inspection paperwork. It checks its own reading against the drawing, and it puts every reading it isn't sure of in front of a person.

DrawingReadCheckedBalloonedReviewedPaperwork

A new part drawing arrives, dimensioned in millimeters.

File: NV-4410-03_RevB.pdf
Part: Drive shaft NV-4410-03, Rev B
Units: Millimeters

Until now, somebody numbered every callout by hand and worked each size out in inches.

What happens next

Nobody numbers it by hand. Here's every step, and everything it produces.

Each step is marked with what does the work. The AI reads. Plain software checks, places, converts and fills in the forms. A person reviews.

It reads the drawing

Each page goes to the AI at full resolution. It reports every callout you'd balloon: sizes, angles, threads, GD&T frames and surface finish marks. It copies each tolerance exactly as printed, signs and all, and notes where the callout sits on the sheet.

It's told to skip the title block, the revision table and the border letters, and never to report a callout that isn't printed. On this sample it got one wrong, the first row. That's what the next step is for.

Read: NV-4410-03_RevB.pdf, sheet 1
Found: 8 callouts

As read	Type	Tolerance as printed
580	Dimension
42.50	Dimension	±0.10
Ø40.00	Dimension	-0.20/-0.30
Ø16.05/15.95	Dimension	16.05/15.95
R0.5	Dimension
M8x1.25	Thread
Ra 0.8	Surface finish
⊥ 0.05 A	GD&T

Plain software

It checks every number against the drawing itself

Most drawing PDFs carry the printed text underneath the picture. Plain software lines up every number the AI read against that text. A match gets marked. A near miss, like a dropped decimal point, gets corrected from the drawing and flagged so someone confirms it. A number that isn't printed anywhere gets flagged too.

The drawing's own text also settles what a number is. A value next to Ra is a surface finish, and it can never be turned into inches. Then each reading gets a score from that evidence, not from how sure the AI says it is.

Checked: 8 readings against the drawing's printed text

Ø40.00 -0.20/-0.30Matches print

42.50 ±0.10Matches print

580, drawing says 58.0Corrected

R0.5Not in text

Ra 0.8Surface finish

M8x1.25Thread

Plain software

It lists what nobody claimed

Next it counts every number printed on the sheet and lists the ones no reading claimed. Table cells and title block values get summed up in one line. Anything that looks like a dimension the AI may have missed gets its own button, and one click adds it with a balloon at that spot.

So a miss shows up on screen instead of staying silent. On a scanned drawing there's no printed text to count, and the tool says so.

Sheet 1: Unclaimed numbers on this sheet (8)

We claimed 14 of the 22 numbers on this page.

Possible missed dimensions (1)

+ 12.0

The other 7 unclaimed numbers read as table cells, title-block values, zone markers or notes.

Plain software

It places the balloons

Every callout you inspect gets a numbered balloon and a short leader. Plain geometry decides where each one goes: clear of the drawing's own lines and the other balloons, close to its callout. No AI in this step, so the same drawing gets the same balloons every time.

Surface finish and GD&T balloons can be switched off if you don't balloon them. Balloons can be moved, renumbered or locked in place.

Placed: 8 balloons, sheet 1

Plain software

It converts to inches

Only a real size ever gets converted, and it's plain arithmetic: millimeters divided by 25.4, rounded to one more decimal place than the drawing used. Tolerances keep their printed signs, so a -0.20/-0.30 band stays under the size. A limit size printed as a max and a min converts as the band it is. A fit like H7 gets expanded to its actual limits.

Tight tolerances keep the digit that matters. A ±0.02 mm tolerance shows as ±0.0008", because rounding it to ±0.001" would pass a part the drawing rejects.

Converted: NV-4410-03, sheet 1

Bal	On the drawing	In inches
1	58.0	2.283"
2	42.50 ±0.10	1.673" ±0.004"
3	Ø40.00 -0.20/-0.30	1.575" -0.008"/-0.012"
4	Ø16.05/15.95	0.630" ±0.002"
8	R0.5	0.020"
5	M8x1.25	Not converted
6	Ra 0.8	Not converted
7	⊥ 0.05 A	Not converted

Plain software

Your inspector reviews it, worst first

This is where a person stays in the loop. The review screen puts every doubtful reading at the top and says why, in plain words, with what to do about it. Your inspector confirms it, fixes it, or throws it out.

They can change what type a callout is, mark it critical, major or standard, and add anything that was missed. A reading a person has confirmed stays confirmed.

Review: NV-4410-03 · 2 need a look

1
Dimension58.0Corrected
We corrected this value from the drawing's own text. Confirm it reads right.
8
DimensionR0.5Not in text
This value isn't in the drawing's text layer. Read it off the print before you accept it.
2
Dimension42.50 ±0.10Matches print
5 more rows match the print.

On every row

Accept, correct the value, change the type, set how critical it is, move or renumber its balloon, or delete it.

Plain software

It builds the paperwork

Once the readings are right, everything that goes with the part comes off the same list, so every document agrees with every other one. The ballooned drawing. A print for the machinist with the inch values written in beside each size. A first article inspection report with the characteristic rows already filled in. An inspection plan saying what gets checked in process, on a sample and at final. A spreadsheet of every callout.

The measured results stay blank for your inspector, because the tool reads drawings. It doesn't measure parts.

Export: NV-4410-03, ready to print

PDFBallooned drawing · balloons on the original PDFPrint for the machinist · inch values beside each size PDFConversions only · inch values, no balloons XLSXCharacteristic list · also as CSV

Report: First article inspection, Form 3
Part: NV-4410-03, Rev B

Char	Requirement	Result
1	2.283"
2	1.673" ±0.004"
3	1.575" -0.008"/-0.012"
6	Ra 0.8
7	⊥ 0.05 A

Part and material details for Forms 1 and 2 are typed in once. Form 3 fills from the drawing.

Plan: Inspection plan, NV-4410-03
Sample: 1 in 10

Char	In process	Sample	Final
3	✓	✓	✓
4	✓		✓
2		✓	✓

First piece inspection required: operator and inspector both sign.

Plain software

It files them where your parts live

Pick which files to keep and which folder of your parts library they go in, and they're saved in one step. If a file with that name is already there, it keeps both instead of writing over it. Nobody downloads, renames and drags files around by hand.

Save to: Parts / NV-4410-03

Ballooned drawing (PDF)Saved

Print for the machinist (PDF)Saved

Characteristic list (XLSX)Saved

Where the AI is, and where it isn't

AI does the reading. Plain software does the checking and the math.

Reading each page of the drawing and finding every callout you'd balloon
Telling what each one is, including a bare number sitting inside a surface finish symbol
Copying each tolerance exactly as printed, and noting where it sits on the sheet

Plain software

Checking every number against the drawing's own printed text, and correcting or flagging what doesn't match
Scoring each reading on that evidence, putting the doubtful ones first, and listing every number nobody claimed
Placing the balloons, converting to inches, and filling in every form, file and folder

AI is very good at reading a drawing it has never seen before. It isn't exact, so it never gets the last word here. Every number it reads is checked against the drawing itself, every inch value comes from plain arithmetic, and anything doubtful is put in front of a person first.

The numbers so far

Measured on the hardest drawing I test it against.

I keep one dense metric drawing with every number on it checked by hand, and score the tool against it. Here's the first version next to the current one.

82% of the callouts on that drawing found on the first pass, up from 14% in the first version. Live runs land between 74% and 82%, and what it misses shows up in the unclaimed list.

11 of 11 surface finish, GD&T and angle callouts correctly kept out of the inch conversion, up from 0 of 11.

5 of 5 toleranced sizes converted with the right band, including limit sizes and all-minus bands, up from 1 of 5.

16% of balloons landed on something that isn't a callout, down from 94%. Each one is plain to see on the sheet and gets removed in review.

As of July 2026. These come from testing, not months of daily use: the same hand-checked drawing run through the first version and the current one, so you can see how far the checking moved it.

It had to earn it

Almost every tool I've built broke the first time it met real drawings. This one did too.

One of the first real drawings I ran through it, a dense metric sheet, came back wrong four ways. Surface finish marks were read as lengths and converted to inches. A diameter lost its decimal point and came back ten times too big. Balloons pointed at empty paper. And every row said it was 85% sure, so nothing got flagged. I said it plainly at the time: "if we can't do a drawing like this, the tool is useless."

0.063"→Ra 1.6, as printed Printed on the drawing: a surface finish of Ra 1.6, in microns. Converting it like a length is off by a factor of 1,000.

The decimal point turned out to be about one pixel wide in the image the AI was being sent. So now each page goes at full resolution. The drawing's own text decides what a number is and whether it can ever become inches. Every reading is checked against that text, and the confidence comes from the evidence instead of the AI's say-so. That's what making one of these hold looks like. You run it on the strange drawings, find what breaks, and fix why it broke.

Built once, adapted to yours

This is the baseline. Yours fills in your paperwork.

Everything above is the tool as it runs today. The parts that do the hard work stay the same. The paperwork it produces, and the way your people measure, get fitted to your operation.

What stays

Reading every callout on the drawing
Checking each reading against the text printed in the PDF
Numbered balloons, and sizes and tolerances converted
The doubtful readings listed first, with the reason, for a person to review

What gets adapted

Your inspection report and first article formats
The units and tolerance conventions you work in
Which paperwork each customer needs
Who reviews the readings

Customer formats

The first article form each customer asks for, filled in from one reading of the drawing.

Incoming inspection

Purchased parts checked against the supplier's drawing before they go on the shelf.

Metric or inch

Converted in whichever direction your people measure.

How it gets set up

It runs next to your inspectors before anyone relies on it.

Connect it to your company login and your file library.
It runs in a browser on top of the systems you already use. Nothing gets replaced.
Set it up around how you inspect.
Which callouts get a balloon, how critical characteristics are checked at each stage, and the fields on your inspection forms.
Run it on drawings you've already done by hand.
Put its output next to paperwork your inspectors already finished, so you can see where it's right and where it isn't before anyone depends on it.
Hand it to your quality team.
They upload, review what's flagged, and export. Every reading it isn't sure of keeps coming to a person.

Quoted up front, no hourly billing. I host it and keep it running, and a care plan covers fixes and changes as your drawings change. The code is yours, and I'll transfer it to you at any time.

Linked Operations · AI implementation for manufacturers

If someone in your operation balloons drawings by hand, let's talk.

Tell me what drawings come in, what paperwork has to go out with the parts, and who does that work today. I'll tell you straight whether a tool like this fits, whether something lighter would do, or whether it isn't worth it for you.

Email Jason →

Jason Markham

Nearly 25 years in manufacturing, including a decade running a machine shop. I build these tools myself.

I help manufacturers and distributors implement AI, automate workflows, and reduce errors with small, focused software builds that take over the back office work: the data, the paperwork, the busywork between the systems they already run.

[email protected]