DIY: How to Reverse Engineer a Part from a 2D Scan

Updated Dec 23, 2020
How to create a reverse engineered design

We often get asked if it’s possible to scan a physical part or component and recreate it with a CNC machine. The answer is yes, you can! Many of our users have reverse-engineered simple parts, like gaskets and seals, with Scan2CAD. Though the process can be quite complex, it’s a great way to recreate a part that is no longer manufactured or cannot easily be purchased off-the-shelf. In this article, we’ll help walk you through one of the most complicated parts of the process: converting your scan from raster to vector. Creating a good-quality CAD file is essential for ensuring good results, and the easiest way to create it is using Scan2CAD. Read on to learn how!

What is reverse engineering?

Reverse engineering is the reproduction of another manufacturer’s product based on a detailed examination of the product’s construction. This process usually involves taking apart a device to see how it works, or producing 3D images of the original part. It’s possible to reverse-engineer almost anything—a mechanical device, an electronic component, computer software or even organic matter! However, whilst some reasons for extracting design information can be socially beneficial (detecting vulnerabilities, or competitive analysis), other uses of reverse engineering are criminal (creating knock-off software or parts). Make sure, therefore, that you’re acting within the law when reverse-engineering a part.

From Scanned Part to CAD File | Reverse Engineering with Scan2CAd

On the left is a simple part made from sheet metal. On the right, we’ve converted the part into CAD format for reproduction. Image source:

What you need:

  • A simple part you’d like to reverse engineer
  • Access to a good quality scanner that can scan the dimensions you need
  • A raster-to-vector converter like Scan2CAD
  • A CNC machine (or access to a CNC machining service) — check out our guide to CNC kits for beginners for tips!


Bonus Video: How To Reverse Engineer A Tool

In this video, Luke will demonstrate how to take an image of a tool and convert it to an accurate vector outline.


Step 1: Scan the product

A critical element of the reverse engineering process is getting a good scan. Since we’re reverse engineering parts based on a 2D scan, you can only choose parts that have details in 2D. We’re only tracing part outlines here, so this technique won’t work for molded parts with extruding 3D detail. You should also take note of the requirements and limitations of your CNC cutting system. For example, the cut width of the tools in your CNC cutting system may limit the amount of detail you want to reproduce.

Deskan Fast Parts Reverse Engineering CNC -- Scan2CAD client

This is a Deskan Fast Parts scanner, which can scan parts up to A0 in size, for more niche reverse engineering situations. For the simplest parts, you could even use your regular desktop scanner!

Expert Tips for getting a good scan
  • Scan your images in high resolution (The rule of thumb is that all lines should be 4 pixels thick!)
  • Try and avoid shadows, which prevents us from seeing the details of the design
  • Save the scan as TIFF image format instead of JPEG. This means that the quality of your image will be maintained, and your image won’t be affected by lossy compression
  • Scan your part at a scale of 100%, so that the resulting image will be the same size as your part
  • If your part is very dark, it’s a good idea to spray paint the part in yellow (or another bright colour), so that you can distinguish the part from any shadows
  • Check your scan for distortion. One way to do this is to use graph paper in the background of your scan, and compare the scanned image against the real part
  • Spend 10 minutes cleaning up the image after scanning, such as by smoothing hairy lines, removing dust and speckles and thickening lines. Check out this guide for 10 raster effects to optimize your vector conversion.

Step 2: Convert image to vector

Once upon a time, this would have been one of the most difficult parts of the process, as you would have had to trace over the image by hand. Thanks to Scan2CAD, it now takes just a few seconds. Simply open your scanned raster image file in Scan2CAD, choose the right vectorization settings, and convert your image in a few clicks! Here’s a quick and easy guide on how to convert your image from raster to vector.

Converting raster image to vector with Scan2CAD


Step 3: Check the vector file

New users sometimes make the mistake of expecting their converted vector image to be the finished article. Before machining your design, you’ll need to spend some time checking and cleaning your vector image. How long this takes will depend on the complexity of your image.

Checklist: Clean up your vector file
  • Check that all the elements are recognized correctly. This includes checking that lines are perfectly straight; corners have right angles; and so on.
  • Convert separate arcs and Bezier curves into polylines. Taking this step ensures that your vector file will be compatible with all CNC machines. With Scan2CAD, you can convert from Bezier curves to Polylines in just a few clicks!
  • Join (or extend) vectors to create smooth, connected vectors wherever possible. To do this, turn on the Between Ends Snap function and select grab points that you’d like to connect.
  • Save the vector image in the correct scale.

Once your image is cleaned up, save your image type using the CNC file format. This ensures that it can be fed into a CNC machine. If you’re not experienced with CNC, then consult with a CNC machinist, who will be able to advise you on the best steps to take for your design.

Reverse engineering more complex parts using 3D laser scanners
If you’ve got a more complicated part to reverse-engineer, you may have to look for 3D laser scanning services. A 3D scanner measures the object using complex technologies like coordinate measuring machines and laser triangulation, amongst other techniques. This is to collect data on the item’s shape and size. The data is then used to construct three-dimensional models of the part. Whilst this process is often costly and time-consuming, it can be one of the best ways to reproduce complex parts.

Want extra tips on how to convert to vector? Check out our Ultimate Guide to Raster to Vector Conversion! Plus, get great tips on turning your ideas into reality with CNC! Having some trouble? Visit our guide to common conversion problems.

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