<p>There is the capable but somewhat expensive <a href="http://www.scan2cad.com/" rel="nofollow" title="Scan2CAD">Scan2CAD</a>.</p>

<p>Otherwise, if you're happy with outlines and not centre lines, scan b&amp;w, aggressively clean up macules, mask off text, and then vectorize in potrace, autotrace, etc. Alternatively, load the bitmap at the correct resolution into a drawing package as a raster layer and draw the lines/objects you want over it. This avoids the horrors of dotted lines.</p>

<p>Both ways are quite a bit of work, sadly.</p>

CC BY-SA 3.0
2016-03-14T18:31:54.527Z
2016-03-14T18:31:54.527Z
scruss
<p>I would recommend using something like <a href="http://www.getpaint.net/index.html" rel="nofollow noreferrer">Paint.NET</a> to "fix" the images before attempting to convert them to CAD.</p>

<p>To my knowledge, most of the Image-to-CAD applications are going to use the grayscale intensity of each pixel to get the Z-axis value. So, you can help this process by pre-filtering the image into grayscale and playing with the contrast until you get enough distinction between the features you want to stand out in your CAD model or print. Here's a quick example using a sample image:</p>

<p>Poor Contrast
<a href="https://i.sstatic.net/JuyOg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/JuyOg.png" alt="Poor Contrast"></a></p>

<p>Better Contrast
<a href="https://i.sstatic.net/yEjjk.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/yEjjk.png" alt="Better Contrast"></a></p>

<p>Whichever program you use will generally have an easier time detecting the edges of the flower pedals in the second image the further towards the center it goes.</p>

<p>GIMP has <a href="https://www.gimp.org/tutorials/Color2BW/" rel="nofollow noreferrer">greyscale</a> and <a href="https://www.gimp.org/tutorials/ContrastMask/" rel="nofollow noreferrer">contrast</a> tools as well.</p>

CC BY-SA 3.0
2016-03-14T20:09:05.710Z
2016-03-14T20:09:05.710Z
tbm0115
<p>I used Corel Draw with good results in professional setting. It's not a breeze - first you clean up the bitmap as well as you can in a bitmap editing program like Photoshop or Gimp - use gradient tool to make the brightness of background roughly even across the entire image, then 'curves' to enhance content and white-out backgrounds, then you import it to Corel and tweak the vectorization settings to produce actual vector borders for the lines (as opposed to tracing edges of individual pixels on one end of the scale, or cutting corners and turning circles into octagons on the other end.) Once you have the image vectorized, you still need to delete all the &quot;floaters&quot; manually - dust specks and so on. The results though can be &quot;good enough for production&quot;.</p>

CC BY-SA 4.0
2023-09-27T09:34:24.443Z
2023-09-27T09:34:24.443Z
SF.
<p>My pictures are saved in PDF. I have used the <a href="https://dwg.autodwg.com" rel="nofollow noreferrer">AutoDWG</a> conversion tool before. It's very awesome. You can try their free online conversion service first. You don't need to download and install, you don't need to register, you can directly convert the PDF in your hand into dwg or dxf, which is very convenient. If the conversion result is not ideal, then download and install the offline version of the software, which is more powerful on raster pdf and can obtain more free conversion opportunities.</p>

CC BY-SA 4.0
2023-09-26T06:24:14.073Z
2023-09-26T06:24:14.073Z
Tonyheideman
<p>I have some design diagrams only on paper. Scanning them to bitmaps is easy, but I've had no luck getting useful vectors out of them. I've tried vectorizers in programs like gimp, and a few online services. Generally, I end up with enormous numbers of spurious vectors (from dust, dotted lines, text on the  diagram, slightly variations in scanning contrast, etc).</p>

<p>What tools and/or techniques can I use to get a more useful vector result, that I can then modify in a normal CAD tool without spending absurd amounts of time cleaning it all up first?</p>

<scanning><cad>
Scan to vector?
TextGeek
# Scan to vector?

(Asked by: username_0 on 2016-03-14)

I have some design diagrams only on paper. Scanning them to bitmaps is easy, but I've had no luck getting useful vectors out of them. I've tried vectorizers in programs like gimp, and a few online services. Generally, I end up with enormous numbers of spurious vectors (from dust, dotted lines, text on the diagram, slightly variations in scanning contrast, etc).

What tools and/or techniques can I use to get a more useful vector result, that I can then modify in a normal CAD tool without spending absurd amounts of time cleaning it all up first?

**Tags:** scanning, cad

---

## 4 answers

### Answer by username_1 on 2016-03-14. Score: 2

There is the capable but somewhat expensive [Scan2CAD](http://www.scan2cad.com/ "Scan2CAD").

Otherwise, if you're happy with outlines and not centre lines, scan b&w, aggressively clean up macules, mask off text, and then vectorize in potrace, autotrace, etc. Alternatively, load the bitmap at the correct resolution into a drawing package as a raster layer and draw the lines/objects you want over it. This avoids the horrors of dotted lines.

Both ways are quite a bit of work, sadly.


---

### Answer by username_2 on 2016-03-14. Score: 1

I would recommend using something like [Paint.NET](http://www.getpaint.net/index.html) to "fix" the images before attempting to convert them to CAD.

To my knowledge, most of the Image-to-CAD applications are going to use the grayscale intensity of each pixel to get the Z-axis value. So, you can help this process by pre-filtering the image into grayscale and playing with the contrast until you get enough distinction between the features you want to stand out in your CAD model or print. Here's a quick example using a sample image:

Poor Contrast
[![Poor Contrast](https://i.sstatic.net/JuyOg.png)](https://i.sstatic.net/JuyOg.png)

Better Contrast
[![Better Contrast](https://i.sstatic.net/yEjjk.png)](https://i.sstatic.net/yEjjk.png)

Whichever program you use will generally have an easier time detecting the edges of the flower pedals in the second image the further towards the center it goes.

GIMP has [greyscale](https://www.gimp.org/tutorials/Color2BW/) and [contrast](https://www.gimp.org/tutorials/ContrastMask/) tools as well.


---

### Answer by username_3 on 2023-09-27. Score: 0

I used Corel Draw with good results in professional setting. It's not a breeze - first you clean up the bitmap as well as you can in a bitmap editing program like Photoshop or Gimp - use gradient tool to make the brightness of background roughly even across the entire image, then 'curves' to enhance content and white-out backgrounds, then you import it to Corel and tweak the vectorization settings to produce actual vector borders for the lines (as opposed to tracing edges of individual pixels on one end of the scale, or cutting corners and turning circles into octagons on the other end.) Once you have the image vectorized, you still need to delete all the "floaters" manually - dust specks and so on. The results though can be "good enough for production".


---

### Answer by username_4 on 2023-09-26. Score: -3

My pictures are saved in PDF. I have used the [AutoDWG](https://dwg.autodwg.com) conversion tool before. It's very awesome. You can try their free online conversion service first. You don't need to download and install, you don't need to register, you can directly convert the PDF in your hand into dwg or dxf, which is very convenient. If the conversion result is not ideal, then download and install the offline version of the software, which is more powerful on raster pdf and can obtain more free conversion opportunities.


---

