How to use Scan2CAD raster to vector conversion software

This page outlines the basic steps you need to take to convert a raster image to vectors using Scan2CAD.

A better guide is Andrea's Real World Guide to Vectorization, a PDF document written by Softcover's Andrea Tribe. Andrea has used Scan2CAD to vectorize hundreds of images of different types and quality. The Real World Guide tells you how to handle less than perfect scans and how to tweak vectorization settings. It will help you to get the best possible vectorization from any vectorizable image.

The Real World Guide can be accessed by going to Scan2CAD's Help Menu, then selecting Real World Guide. It is also available in French.

If you have any questions or problems using Scan2CAD, email us!

How to convert a raster image with no text
How to convert a raster image with text
How to create a color DXF file from a color raster image

How to convert a raster image with no text

Use this method if your drawing contains no text or the text is too poor quality to be vectorized using OCR (optical character recognition).

The Warning: Color Image dialog appears when you load an image that contains more than two colors. These instructions assume that you have not turned off the Warning: Color Image dialog. If you have, you can reactivate it by reinstalling Scan2CAD.

  1. Click to load a BMP, TIFF etc. raster image or scan a drawing using File > Acquire.

    The Warning: Color Image dialog may appear. If it does:

    1. Select the second option.
    2. Click OK. If a warning appears, click Yes. You will enter Scan2CAD's Simple Threshold dialog.
    3. Move the slider to a position where the lines on your image are as solid as possible and the background is as clean as possible.
    4. Click OK.

  2. Work through the Raster Quality Checklist.

    The most common reason for poor vectorization results is a poor quality raster image. You must work through the Raster Quality Checklist even if you think your raster image is perfect. Your image may look fine when viewed full screen but once you zoom into it and look properly you may find that it is not as good as you think.

    If the raster image is good enough quality to vectorize:

  3. Optional but recommended: Click (Raster Effects > Smooth) to smooth the raster lines.

  4. Ensure you can see your entire drawing on the screen. If you can't, click to zoom out.

  5. Go to the Type Menu. This contains vectorization settings.

    • Choose the setting that best describes the raster image - Architectural, Electrical, Mechanical, CNC Profile, Site Plan or Contour Map.
    • If your drawing is a solid shape to be outlined, choose Outline.

  6. Vectorize the raster image by clicking . Any text will be converted to short lines.

  7. Optional: View the vectors -

    • Click or press the V key to view Vectors only.
    • Click or press R to view the Raster image only.
    • Click or press B to view Both.
    • Press Shift+F to fade the raster image so that it's easier to see the vectors on top.
    • Press C to toggle viewing vectors by Color or by type.
    • Press G to toggle the display of Grab points at vector ends.

  8. Save the vectors as a DXF file by going to File > Vector > Save As.

How to convert a raster image with text

Use this method if your drawing contains clear, sharp text characters.

The Warning: Color Image dialog appears when you load an image that contains more than two colors. These instructions assume that you have not turned off the Warning: Color Image dialog. If you have, you can reactivate it by reinstalling Scan2CAD.

  1. Click to load a BMP, TIFF etc. raster image or scan a drawing using File > Acquire.

    The Warning: Color Image dialog may appear. If it does:

    1. Select the second option.
    2. Click OK. If a warning appears, click Yes. You will enter Scan2CAD's Simple Threshold dialog.
    3. Move the slider to a position where the lines on your image are as solid as possible and the background is as clean as possible.
    4. Click OK.

  2. Work through the Raster Quality Checklist.

    The most common reason for poor vectorization results is a poor quality raster image. You must work through the Raster Quality Checklist even if you think your raster image is perfect. Your image may look fine when viewed full screen but once you zoom into it and look properly you may find that it is not as good as you think.

    If the raster image is good enough quality to vectorize:

  3. Work through the Raster Text Quality Checklist.

    Scan2CAD's OCR text recognition will only recognize raster text where the following conditions are met:

    • The raster text is easily legible.
    • The raster text characters do not touch each other.
    • The raster text characters do not touch other drawing elements.
    • The raster text characters are not at different orientations.

    • The raster text characters are in a font that Scan2CAD can recognize.

    Use the Raster Text Quality Checklist to ensure that your text meets these conditions. If the raster text meets these conditions:

  4. Optional but recommended: Click (Raster Effects > Smooth) to smooth the raster lines.

  5. Go to the Type Menu. This contains vectorization settings.

    Choose the setting that best describes the raster image - Architectural, Electrical, Mechanical, CNC Profile, Site Plan or Contour Map.

  6. Tell Scan2CAD the size of text to expect:

    1. Go to OCR > Char Size.
    2. Zoom into the biggest character on the image by placing your cursor over it and pressing the M (Magnify) key several times, until you can see the character clearly. You can also zoom in by scrolling your mouse wheel forwards.
    3. Click on a black part of the character. It becomes enclosed in a box.
    4. Click to zoom out.

  7. Vectorize ALL the raster image (i.e. both drawing elements and text) by clicking .

  8. Optional: View the vectors -

    • Click or press the V key to view Vectors only.
    • Click or press R to view the Raster image only.
    • Click or press B to view Both.
    • Press Shift+F to fade the raster image so that it's easier to see the vectors on top.
    • Press C to toggle viewing vectors by Color or by type.
    • Press G to toggle the display of Grab points at vector ends.

  9. Save the vectors as a DXF file by going to File > Vector > Save As.

After vectorizing your drawing you may want to correct the vectorized text using OCR > Dictionary (Pro and demo versions only).

How to create a color DXF file from a color raster image

The Warning: Color Image dialog appears when you load an image that contains more than two colors. These instructions assume that you have not turned off the Warning: Color Image dialog. If you have, you can reactivate it by reinstalling Scan2CAD.

  1. Click to load a BMP, TIFF etc. raster image or scan a drawing using File > Acquire.

    The Warning: Color Image dialog appears. Select the fourth option and click OK.

  2. Go to Palette > Reduce Colors Auto. Select a manageable number of colors, e.g. 32.

  3. Go to Palette > View/Edit Palette and group together similar colors:

    1. Select all the shades of a particular color, e.g. all shades of red. You can do this by clicking on the colors you want to select in the palette on the right, by clicking on them in the Preview Window on the left or a mixture of both. (You may find this easier if you select the Hue option in the dialog.)
    2. Click on .
    3. Click on one of the colors you selected in (a). The Pick box changes to this color.
    4. Click the Preview Change button. The colors you selected in (a) are changed to the color you selected in (c). You can see the change in the Preview Window.
    5. Repeat (a) to (d) for all color groups on the image - whites, blues, greens etc.
    6. Click OK.

  4. Double click your left mouse button or press the U key to Unselect any selected color.

You now have two options.

Option 1

This option is better because it uses color information while vectorizing.

  1. Go to Palette > Select Separation Colors. Click on the colors you want to vectorize and click OK.
  2. Follow Step 2 onwards of How to convert a raster image with no text or How to convert a raster image with text.

Option 2

Use this option if you were unable to group the colors cleanly in Steps 2 and 3 above.

  1. Follow Step 2 onwards of How to convert a raster image with no text or How to convert a raster image with text but just before you save the DXF file go to Vector Edit > Vector Colors to Raster Colors.

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