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Generate from Path

This group of effects creates new objects from one or more existing paths.

Blur Edge

Renamed to Inside/Outside Halo in v0.45 so as not to be confused with blurring using filters.

Dimensions

New in v0.46.

Adds «CAD» style dimension arrows to an object. Only works on paths. It uses an object's quadro delimitatore to determine placement of arrows. The arrows and original object are placed inside a Gruppo.

Dimensions example.
Two examples of using the Dimensions Effect. The square was converted to a path prior to applying the effect.

Extrude

Simulates motion. Draws a copy of the selected object behind the original and then connects corresponding nodes with lines to form a group of closed paths. The direction and offset of the copied object can be specified. The new objects inherit the attributes of the original but can be edited as a group.

Extrude example.
Left: Original object. Right: Object with extrusion. (Magnitude of 25, Direction of 180.) The Master opacity has been set to 0.5 for the new objects.

One can also use this effect to simulate perspective by reducing the size of the copy along with the associated nodes. The steps are:

  • Ungroup objects (Oggetto → Dividi (Shift+Ctrl+G)).
  • Combine into one path (Tracciato → Combina (Ctrl+K)).
  • Use Strumento Nodo to select all nodes associated with copy in back.
  • Move nodes toward each other (<, etc.).
  • Break apart path (Tracciato → Separa (Shift+Ctrl+K)).
  • Group objects (Oggetto → Raggruppa (Ctrl+G)).
Extrude example 2.
Left: Without perspective. Right: With perspective.

Inside/Outside Halo

This effect produces a blurred image of the selected object(s). It works by making multiple copies of the object(s) and insetting or offsetting the path of each copy by a different small amount. The opacity of each copy is set to a small value based on the number of copies made. The copies are embedded in a group that is left above the original object(s).

Why would you want to use this effect when Inkscape now supports filters? Well, Filter support in Web Browsers is still in its infancy. Your SVG drawings are more likely to be properly rendered using this effect. The look of the blur is also a bit different.

This effect only works on paths! Convert regular shapes and text to paths before using (Tracciato → Da Oggetto a Tracciato (Shift+Ctrl+C)).

Inside/Outside Halo example.
Top: Regular shapes. Middle: Regular shapes after using Inside/Outside Halo effect (Width: 5, Number of steps: 11). Bottom: After deleting the original objects.
Inside/Outside Halo example 2.
Text after using the Inside/Outside Halo effect to produce a shadow. The shadow has been shifted down and to the right. The color of the text was changed after creating the shadow. The original text was moved above the shadow in z-order (Width: 5, Number of steps: 11).

Interpolate

Draws a series of lines that interpolate the space between two paths. The options include setting the number of Interpolation Steps (in-between lines), an Exponent factor that controls the spacing between interpolated paths (zero for even spacing), specifying if the original paths should be duplicated (Duplicate Endpaths), and specifying that the path style should also be interpolated. Objects need to be converted to paths prior to invoking the effect.

Interpolation example.
An interpolation between the red and blue lines, with the Interpolate Style box checked.

The beginning of the path of one object is matched to the beginning of the other path. This can lead to unexpected effects. The starting point of a path can be found by selecting the path with the Node Tool and then using the Tab key. If no node is already selected, the first node in the path will be selected.

Interpolation example 3.
An interpolation between the blue square and a red circle, with the Interpolate Style box checked. Left: the start of the two paths (indicated by the crosses) are not in the same relative positions. Right: the circle has been rotated 135 degrees so the start of the two paths are in the same relative positions.

The interpolation effect can also be used to simulate gradients of different symmetries. When calling the effect, the smaller path should be selected first.

Interpolation example 5.
From left to right: Interpolation between two squares in the same orientation; two squares, one rotated 90 degrees; two stars in the same orientation; a star and a circle. The starting paths are shown on top. In all cases, the number of Interpolation steps was set to 25. Note that the smaller path must be selected first.

Pattern Along Path

This effect places a pattern along one or more target paths. The pattern can be a single object or a Gruppo of objects. See also la sezione chiamata «Live Path Effects (LPE) » for an alternative way of putting patterns along paths.

Pattern along Path example.
Copies of the single blue star are placed along a path (shown in red). The star is deformed to follow the path.

To put a pattern on a path:

  1. Select the pattern:  The pattern can be a single object or a Gruppo. In some cases, you may have better results if you explicitly convert all objects (e.g., forme) in the pattern to paths.

  2. Select the target path or paths:  Called the Skeleton path by the effect author.

  3. Call the effect:  A dialog will open up where various parameters can be selected. After the effect is applied there will be a new path for each object in the pattern. For example, the 18 stars on the red line in the above figure are formed by one path.

The quadro delimitatore of the pattern is used for placing the pattern along the path, with the quadro delimitatore of one pattern copy touching the quadro delimitatore of the next copy (if no additional spacing is specified).

When the effect is called up, the following dialog is shown:

Pattern along Path effect dialog.
The Pattern along Path effect dialog. The dialog is described below.

This dialog has many options that can be set (see figures below for examples of use):

  • Copies of the pattern:  You can choose to have a Single copy of the pattern placed on the path or multiple copies Repeated along the path. The pattern can be stretched so that the left edge of the first pattern copy lines up with the start of the Skeleton path and the right edge of the last pattern copy lines up with the end of the Skeleton path.

  • Deformation type:  Two options are available:

    • Snake:  The pattern is rotated and deformed to follow the path such that all points with the same horizontal (x) position in the pattern will be on the same normal to the path, and all points with the same vertical (y) position in the pattern will be placed the same distance from the path. If the Pattern is vertical box is checked, then the pattern is rotated 90 degrees first.

    • Wave:  The pattern is deformed only in either the vertical or horizontal direction to conform to the path. The direction of the deformation is controlled by the Pattern is vertical check box described below.

  • Space between copies:  You can add (or subtract) space between copies of the pattern. The unit is pixel.

  • Normal offset:  The normal offset moves the pattern perpendicular relative to the path. Positive values move the pattern to the left relative to the direction of the path.

  • Tangential offset:  The tangential offset moves the pattern in the direction of the tangent line to the path.

  • Pattern is vertical:  Checking this box rotates the orientation of the pattern by 90 degrees.

  • Duplicate the pattern before deformation:  With this box checked, the original pattern is left in place. Otherwise, it disappears.

Pattern on Path example 1.
Left: Snake deformation, right: Wave deformation. From top to bottom: Copies of the pattern: Single; Single, stretched; Repeated; Repeated, stretched.
Pattern on Path example 2.
Left: Snake deformation, right: Wave deformation. All with spacing of 10 px. From top to bottom: Spacing only, Normal offset of 5 px, Tangential offset of 10 px, Pattern is vertical.

The Pattern along Path is a very useful effect but it does have a few quirks. One is that if the pattern is moved before use, the results may be less than ideal. Another is that different parts of the pattern can be distorted in different ways as seen below.

Pattern along Path example 6.
The pattern at the upper left was put on the red path. Note how the distortion of the black outline is different from the blue squares. A solution in this case is to use the Add nodes effect to increase the number of nodes in the path of the black square.

The following example shows a pattern placed on both straight and curved paths. If the radius of curvature is too small, the pattern may be grossly distorted.

Pattern on Path example 4.
The pattern at the top of the figure was applied to a straight line and to a curved line (shown in red).

A pattern can be used to create a fancy border as shown below. Care must be taken that the pattern lines up at the corners. This can be done by making the distance between the corner nodes multiples of the pattern width or by breaking the path into disconnected pieces at the corners (use the Break Path at Selected Nodes ( ) option in the Strumento Nodo Controlli Strumento) and using the Repeated, stretched option.

Pattern along Path example 5a.
Borders produced with the Pattern along Path effect. In both cases, the pattern in the center was put on rectangle that was converted to a path. On the left, the rectangle side lengths were chosen to be multiples of the pattern width. On the right, the sides were disconnected by using the Break Path at Selected Nodes ( Pattern along Path example 5a. ) option in the Strumento Nodo-Controlli Strumento on each corner node and the Repeated, stretched option was chosen. This ensured that the pattern would line up at the corners properly.
Pattern along Path example 5b.
From left to right: A single path with a corner point. The lengths of the sides are not multiples of the pattern width; thus, the pattern does not line up at the corner. The path converted to a compound path with two sections by using the Break Path at Selected Nodes ( Pattern along Path example 5b. ) option in the Strumento Nodo-Controlli Strumento on the corner point node. Using the Repeated, stretched option, the pattern width is adjusted so that it lines up at the corner. A close up of corner showing a discontinuity due to the pattern pieces not being connected. A close up of the corner after the two nodes at the corner are connected using the Join Selected End Nodes ( Pattern along Path example 5b. ) option in the Strumento Nodo-Controlli Strumento.

Going one step further, a pattern can be applied to a circle. In the following figure, the pattern on the right was applied to a circle (of larger diameter than the solid yellow circle). The resulting path was filled with a radial gradient.

Pattern along Path example 6.
A sun produced by putting a pattern on a circle. The flame path shown on the right was used as the pattern. A small space was added between pattern copies by setting Space between copies to 10. (The yellow circle is an independent object.)

One use of the Single, stretched option is to put text on a path. The text must be converted to a path first (Tracciato → Da Oggetto a Tracciato (Shift+Ctrl+C)).

Pattern along Path example 7.
The text was placed along the path using the Single, stretched and the Ribbon options. The text was converted to a path first.

Another use of the Single, stretched option is to create flourishes. The steps are:

  • Draw a small circle, convert to a path (Tracciato → Da Oggetto a Tracciato (Shift+Ctrl+C)).
  • Create a «tear drop»: Convert one node to a corner node and move to right. Adjust node handles to flatten lines.
  • Add nodes with Add Nodes effect.
  • Draw curves with Strumento Bezier or Strumento spirale. Use Pattern along Path to put a tear drop along curves.
  • Create multiple curved tear drop paths and combine (Tracciato → Unione (Ctrl++)) to form the flourish.
Pattern along Path example 8.
From top to bottom: Circle converted to path. Path with one node moved and handles adjusted. Path with extra nodes added. Tear drop path put on blue curve path. Ditto.
Pattern along Path example 8a.
Top: Four «tear drop» paths are in position to be combined. Bottom: The final flourish after combining the paths.
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