Turn Old Drawing Photos and Scans Into Editable CAD Files With Your AI Agent

What you get

If all you have is a photo, a scan, a hand sketch, or a CAD screenshot of an old drawing, with no original file, you can install an open-source Skill. Your AI agent can then redraw it as a DWG that you can edit directly in AutoCAD, and overlay the result on the original to check for differences. Three copy-paste prompts are included below.

Here is how the work is split: your AI agent draws the lines and checks its own work, and you make the final call on the key dimensions. For any dimension that is not written on the drawing, the agent only gives an estimate. Always check those by hand before you cut or build anything from them.

Here is the process: you send one image. Your AI agent first checks whether the image is clear enough and whether it shows units. Then it writes every line and every dimension into a list and hands that list to AutoCAD to draw. Finally, it overlays the result on the original and compares the two. If anything is off, it goes back and fixes it.

Check three things first

A Windows PC with AutoCAD installed. The Skill uses AutoCAD to generate and check the DWG. This route does not work on a Mac.
An AI agent that can install Skills. The project is written in Codex's Skill format. Other AI agents that can read Skills may work too, but the author only documents how to install it in Codex.
A clear image, if possible. Shoot the drawing straight on, with even lighting. The results are much better. If the drawing has dimension labels, even better.

You can still get something without AutoCAD. The repository includes an open-source script that can generate a DXF file directly. DXF is a drawing format that most CAD programs can open. This route only traces rough lines, though, and it does not guarantee the dimensions.

Why it is more reliable than a simple image-to-line tool

A basic image-to-vector tool only cares whether the lines look right. This Skill does one more thing: it labels where every important dimension came from, using four levels.

Written numbers come first. Dimensions printed on the drawing, and the data you give it, always take priority over measurements taken from pixels.
It stops when numbers conflict. If two dimensions contradict each other, it does not pick one on its own. It marks the conflict as "needs a human look" and hands it to you.
It gives one final status. Pass, Pass with notes, Needs review, Missing data (cannot be completed), or Failed. It will never vaguely say "done."

Step 1: Have your AI agent set up the environment

Let your AI agent install the Skill and its Python dependencies, then confirm that it can connect to AutoCAD. Copy this:

Help me install this open-source Skill, which redraws images as DWG files for AutoCAD:
https://github.com/pengxiaoan/autocad-dwg-redraw-skill
1. First, read the repository's README and skills/autocad-image-redraw/SKILL.md, then tell me in plain language what environment it needs.
2. Check my computer: Is it Windows? Is AutoCAD installed? Is my Python version new enough? If anything is missing, tell me first. Do not buy or activate any software for me.
3. Install the autocad-image-redraw Skill and the Python dependencies it needs. Ask me before installing each item.
4. After installing, run a dry run that does not connect to AutoCAD, to confirm the script works.
5. Tell me in three to five sentences what was installed and where. If there is a decision I need to make, ask me with multiple-choice questions.

Why it is written this way: AutoCAD is paid software, so the prompt asks the agent to report what is missing and not to activate anything for you. The dry run comes before any real work, so errors are easier to track down.

Step 2: Send the drawing and start the redraw

Drag the image into your AI agent, then send the prompt below. It will ask you a few questions first, such as whether to keep the dimension text and what units the drawing uses. Choose whatever matches your situation.

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Why it is written this way: the five redraw methods match the five modes in the repository. They are listed in plain language, so you don't need to remember the English names. The "inferred" and "unreadable" dimensions go on their own list, so in the next step you only need to check those.

Step 3: Check the overlay and verify only the key dimensions

In the comparison image your AI agent returns, the original and the CAD preview are overlaid, so any differences are easy to spot. You don't need to check every line. Focus on three things:

Dimensions marked "inferred" in the list. Pick the ones that would affect fabrication or construction, and measure them against the original part or on site.
Walls, holes, or arcs that are clearly misaligned in the comparison image.
Whether the final status is "Needs review" or "Missing data."

If you find a problem, tell your AI agent the real dimensions:

I checked these dimensions. Please update them as follows:
[part or label]: [real size and unit]
[part or label]: [real size and unit]
Redraw and compare again after the changes, and list any dimensions that are still unconfirmed.

If you have an original DWG or PDF, switch to a different Skill

The same repository also has autocad-dwg-redraw. If you have the original DWG, it copies the objects from that file directly and checks the count of each one. This is far more accurate than redrawing from a picture. If you only have a PDF, it first converts the PDF into an intermediate drawing and then rebuilds from that. It also tells you which lines came from the PDF's vector data and which were traced. To use it, replace the Skill name in the Step 1 prompt.

Things to watch out for

Don't expect it to be precise enough to cut from directly. Only when the drawing has units and enough dimensions can the results be considered accurate. A drawing that looks right does not mean it measures right.
Special fonts, external references, and custom objects in old drawings often cause problems. After the automatic checks finish, open the file in AutoCAD and look it over yourself.
Straighten a skewed photo before you send it. The more perspective distortion there is, the more the agent has to infer.
The repository does not state an open-source license. Before using it commercially, contact the author to confirm.