I'm reminded of the Xerox JBIG2 bug back in ~2013, where certain scan settings could silently replace numbers inside documents, and bad construction-plans were one of the cases that led to it being discovered. [0]
It wasn't overt OCR per se, end-user users weren't intending to convert pixels to characters or vice-versa.
We’re taking a different path, building a parsing engine that converts CAD (DWG/DXF) into fully structured JSON with preserved semantics (no ML in the critical path).We also have a separate GIS parser that extracts vector data (features, layers, geometries) independently,
Like to know how you handle consistency and reproducibility across runs using models and how you make it affordable, especially at scale. because as far as i know CAD and GIS need precision and accuracy.
OCR accuracy on technical documents is one of those problems that looks 95% solved until you hit the edge cases. Construction docs are especially tricky because of mixed handwriting, stamps, revision clouds, and poor scan quality. Curious how you handle multi-language documents — a lot of international construction projects have specs in two or three languages on the same page.
Looks cool! Where are you getting the data to finetune the cv models for element extraction? I'm worried there isn't a robust enough dataset to be able to build a detection model that will generalize to all of the slightly different standards each discipline (and each firm for that matter) use.
good q — we don't train on customer drawings. Our detection models are trained on a curated dataset of architectural drawings we've sourced and labeled ourselves, focused on the most common fixture and element types across CSI divisions.
The generalization problem you're pointing at is real and it's the hardest part of this. Our approach is to keep the detection scope tight — rather than trying to generalize across every firm's conventions, we train on a small but high-quality set of fixtures and optimize for precision within that scope.
The result is high confidence outputs on the elements we support, rather than mediocre coverage across everything.
We're expanding the detection surface incrementally as we validate accuracy division by division!
Anyone building in or for construction tech — whether that's a startup building estimating or project management software, a construction company with an internal tech team solving this themselves, or a builder looking to automate their workflow. The common thread is drawings. Every one of those groups lives and dies by their ability to extract actionable data from a PDF that was never designed to be machine-readable. We're building the layer that makes that possible so they don't have to start from scratch.
Why does the workflow lie at the level of a real or virtual piece of paper and not in the metadata from the applications used to create that piece of paper? Seems like a CAD tool would allow you to identify each element of the drawing, assigning metadata as required.
Only a small set of construction stakeholders participate in the CAD ecosystem (e.g., architects, large GCs) while a broader set of stakeholders (subcontractors, trades, smaller GCs/CMs) do not receive BIM files and work with PDFs. CAD/BIM is a wonderful aspiration but for many the reality is PDFs.
Re. "CAD/BIM", technically speaking CAD doesn't imply BIM, and the industry's promotion of BIM is akin to AI promotion among software engineering teams - the benefits aren't clear upon detailed review of the advertised capabilities. The CAD part, on the other hand, is generally recognized as the essential tooling for the profession and I'm surprised to hear that it just is a "wonderful aspiration".
Oh you sweet summer child. These draws are anywhere from 0 to 120 years old and might just be something pulled out of a floppy disk from 1970 to scanned in coffee ridden pieces of paper sitting in a desk folded a hundred times.
The world in which metadata is a common thing attached to any file doesn't exist, and probably never will, no matter how much you try to improve CAD work flow.
It is telling that so many of the comments here assume the person with a thing that is not the most practical would be easily able to request thing in a different format. The assumption that the person with the inconvenient thing would never have thought to ask if more convenient thing was available and just willfully toiling with the inconvenient thing is kind of insulting.
So can any type of file -- that doesn't have any relevance to the supposed design of every file type in existence. Now, later versions of PDF do have explicit support for signatures, but what does this have to do with preventing OCR? OCR reads a file, it doesn't change the original file.
Some OCR solutions do change the original file, like OCRmyPDF. They take layers that were just images before and replace it with text layers so that you can search the document.
That isn't OCR, but an application of the resulting output of OCR. Again, a signature on a PDF or any type of file doesn't prevent you from reading it. (It also doesn't technically prevent you from changing it, it just enables the detection of changes to a particular file.)
There's nothing about PDFs or image formats that prevent anyone from doing OCR. The reason construction documents are difficult to OCR is because OCR models are not well trained for them, and they're very technical documents where small details are significant. It doesn't have anything to do with the file format
PDFs are merely an collection of objects, that can be plainly read by reading the file -- some of those are straight up plain text that doesn't even need to be OCR'd, it can be simply extracted. It is also possible to embed image objects in PDFs, (this is common for scanned files) which might be what you are thinking of. But this is not a design feature of PDF, but rather the output format of a scanner: an image. Editing PDFs is a simple matter of simply editing a file, which you can do plainly as you would any other.
I'm reminded of the Xerox JBIG2 bug back in ~2013, where certain scan settings could silently replace numbers inside documents, and bad construction-plans were one of the cases that led to it being discovered. [0]
It wasn't overt OCR per se, end-user users weren't intending to convert pixels to characters or vice-versa.
[0] https://www.youtube.com/watch?v=c0O6UXrOZJo&t=6m03s
Full context and details: https://www.dkriesel.com/en/blog/2013/0802_xerox-workcentres...
The generalization problem you're pointing at is real and it's the hardest part of this. Our approach is to keep the detection scope tight — rather than trying to generalize across every firm's conventions, we train on a small but high-quality set of fixtures and optimize for precision within that scope.
The result is high confidence outputs on the elements we support, rather than mediocre coverage across everything.
We're expanding the detection surface incrementally as we validate accuracy division by division!
The world in which metadata is a common thing attached to any file doesn't exist, and probably never will, no matter how much you try to improve CAD work flow.
I have to make a BOM and oh boy I hate my job
A lot of them are "archival" so I'm pretty OOL
It is telling that so many of the comments here assume the person with a thing that is not the most practical would be easily able to request thing in a different format. The assumption that the person with the inconvenient thing would never have thought to ask if more convenient thing was available and just willfully toiling with the inconvenient thing is kind of insulting.
Also do doors, windows, and mechanical equipment.
dm, and I can include you in the next preview.
Let me know if you find it useful or have any questions, happy to help.
Love to give it to an arc client, not sure who the right person to implement this would be? Hmm…
https://cal.com/anchorgrid/anchorgrid-external-meeting?durat...
There's nothing about PDFs or image formats that prevent anyone from doing OCR. The reason construction documents are difficult to OCR is because OCR models are not well trained for them, and they're very technical documents where small details are significant. It doesn't have anything to do with the file format