Vectorization settings

Vectorization settings control the conversion of raster images to vectors.

The default settings that are set when you select an option from the Type Menu give good results on most drawings but sometimes you may need to edit them.

In most of the illustrations below the raster image is shown in gray and vectors are superimposed in black.

You should also see 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 dash lines are not recognized

Make sure that Type > Settings > Object Identification > Dash Line is selected.

Dash line not selected Dash line selected

In the diagrams above vector end points are enclosed in small squares.

If Dash Line is selected and dash and dash dot lines are still not being identified try increasing the maximum dash and gap lengths in Type > Settings > Advanced.

If arrows are not recognized

Make sure that Type > Settings > Object Identification > Arrow Line is selected.

If arrows are still not identified try increasing the maximum arrow head length in Type > Settings > Advanced.

Arrows will not be recognized where the arrow tip is touching a line that has a similar width to the arrow head. If an arrow is recognized as a line, you can quickly change it to an arrow as follows:

  1. Click .
  2. Right click.
  3. Select Arrow 1 or Arrow 2 from the dialog.
  4. Click on the lines you want to convert to arrows. The arrow head will be at the end of the line you click on.

If polylines are not recognized

Make sure that Type > Settings > Object Identification > Polyline is selected.

Alternatively, use Vector Edit > Make Polylines to create polylines after vectorization.

If hatch lines are not recognized

Make sure that the Hatch option corresponding to the angle of the hatch lines you want to identify is selected in Type > Settings > Object Identification.

If hatch lines are still not identified, try increasing the Hatch Line angle tolerance in Type > Settings > Advanced.

If hatch lines are identified but the lines are not parallel, select the angle in Type > Settings > Angle Optimization that corresponds to the angle of the hatch lines you want to identify.

If arcs or Bezier curves are not recognized

If arcs are not recognized make sure that Type > Settings > Object Identification > Arc is selected.

If Bezier curves are not recognized make sure that Type > Settings > Object Identification > Bezier is selected.

You can choose to identify arcs or Bezier curves.

If the image is a typical architectural, mechanical or electrical drawing containing mainly straight lines, select arc. If the image is mainly curvy, like a contour map, ship hull, aerofoil or freeform artwork select Bezier. If you are vectorizing a curvy image but your CAD or CNC program does not support splines you can still select Bezier. You can convert the Bezier curves to arcs or lines on export using File > Vector > Export Options.

If circles are not recognized

If circles are not recognized make sure that Type > Settings > Object Identification > Circle is selected.

Line Width

If thick lines contain double vectors, increase Type > Settings > General > Line Width.

Double vectors Single vectors after increasing Line Width

If you have to increase Line Width, the lines on your raster image are thicker than normal. Thicker lines have more unwanted protrusions and holes so use Raster Effects > Smooth () and Raster Effects > Clean > Remove Holes () before vectorization. You may want to try rescanning your drawing at a lower resolution to decrease the line thickness.

Deviation Factor

If the vectors do not follow the lines on the raster image closely enough, decrease Type > Settings > General > Deviation Factor.

Loose vectors Tight vectors after decreasing Deviation Factor

If you have to decrease the Deviation Factor you may have scanned your drawing at too low a resolution. You may want to try rescanning it at a higher resolution.

Corner Snap

If corners are chamfered, increase Type > Settings > General > Corner Snap to sharpen them. You may also need to increase Type > Settings > Advanced > Corner Snap Angle Tolerance.

Chamfered corner Sharp corner after increasing Corner Snap

Pass-Thro Snap

If vectors do not cross neatly at untidy raster junctions, increase Type > Settings > General > Pass-Thro Snap.

Untidy junction Neat junction after increasing Pass-Thro Snap

Gap Jump Distance

If the vectors are broken at breaks in the raster image, increase Type > Settings > General > Gap Jump Distance.

Broken vectors Continuous vectors after increasing Gap Jump Distance

If there are a lot of breaks in your raster image you may be able to jump them more effectively if you use Raster Effects > Thicken > Lines () and Raster Effects > Thicken > Pixels () before vectorization.

Loose Ends Length

If you have a lot of loose end vectors, increase Type > Settings > General > Loose Ends Length.

Loose end vectors No loose end vectors after increasing Loose Ends Length

To avoid loose end vectors, use Raster Effects > Smooth () before vectorization.

Connect Thro Nodes

If you want lines to pass at intersections rather than join, select Type > Settings > General > Connect Thro Nodes.

Lines join at intersections Lines pass at intersections

In the diagrams above line end points are enclosed in small squares.

Arcs, Bezier curves and Circles always continue through intersections even if Connect Thro Nodes is off.

Align to current grid

If you want to snap vectors to a grid, select a grid spacing using Vector Edit > Grid Snap Distance.

To view the grid, press Shift+I or select View > View Grid. Note that you will only be able to see the grid when you are zoomed in.

Select Type > Settings > General > Align to Current Grid.

In the diagrams below the raster image and grid lines are shown in gray and the vectors are superimposed in black.

Vectors not snapped to a grid Vectors snapped to a grid

Angle Optimization

If the vectors deviate slightly from their correct angles due to variations in the raster image beneath, select angles in Type > Settings > Angle Optimization. For example:

90/180 = off 90/180 = on

When 90/180 is on, lines within a user-specified tolerance of 90 or 180 degrees are snapped to 90 or 180 degrees.

45 = off 45 = on

When 45 is on, lines within a user-specified tolerance of 45 degrees are snapped to 45 degrees.

If Angle Optimization does not appear to be working, this is because Scan2CAD has chosen not to optimize a line or lines. It may do this if optimizing the line(s) would interfere with the logical position of a node.

If Angle Optimization is set on an image that does not have lines at the angles that have been selected for Angle Optimization, gross distortion of vectors can result:

In this case, turn Angle Optimization off.

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