Spirals

The Spiral tool lets you draw Archimedean spirals and other spirals with a constant divergence power factor. Other types of spirals (e.g. logarithmic) can be drawn using the Function Plotter extension.

Create a spiral object

• Select the Spiral tool from the main Toolbox along the left side of the window. Or use the keyboard shortcuts I or F9.

• Click + Left Mouse Drag to draw a spiral. The center of the spiral will be located where you first clicked.

A modifier can be applied to Spiral creation.

• Press CtrlCmd while dragging the spiral end handle, to rotate the Spiral in 15° steps. The default rotation steps can be changed in Inkscape Preferences Rotation snap angle.

Todo

fix this text link, after the Preferences section has been written.

To reverse the direction of the spiral use the transformation Flip Horizontal (h) or Flip Vertical (v) functions.

By default the spiral object inherits the tool’s own style (Fill:none, Stroke:black,width:1px). This can be changed in the Preferences’ Tools section. Or right-click on the Spiral tool icon, in the main Toolbox, to open its Preferences settings. Or CtrlCmdShiftP.

Todo

fix this text link, after the Preferences section has been written.

The Spiral tool’s style can be modified by:

• Clicking on a color in the palette (Click to set or change the fill color, or ShiftClick to set or change the stroke color).

• Adjusting the color in the Fill and Stroke Dialog.

• Selecting a color with The Dropper Tool.

• Copying and Pasting the style of another object.

Modify a spiral object with mouse

While the Spiral tool is enabled the spiral object will display diamond-shaped modification handles.

The spiral has two modification handles - an outer handle(spiral end) and an inner handle(spiral start).

Drag the inner handle to unwind/rewind the spiral turns from the center.

Drag the outer handle to add/remove spiral turns to/from the outside.

Result	How to Achieve
Edit outer spiral turns in 15° steps	Hold CtrlCmd while dragging the outer handle (Rotation snap angle)
Rotate the spiral	Hold Shift while dragging the outer handle along the direction of the path
Resize the spiral	Hold Shift while dragging the outer handle perpendicular to the direction of path
Rotate the spiral preserving the radius	Holding AltOptionShift while dragging the outer handle (does not resize the spiral)
Rotate spiral in 15° steps	Holding CtrlCmdShift while dragging the outer handle
Return inner handle to center	Press Shift + click inner handle
Change divergence (spacing)	Hold AltOption while dragging the inner handle vertically to increase(down) or decrease(up)
Return divergence to one	Press AltOption + click inner handle

Todo

Fix Rotation snap angle link when Preferences section has been written

Clickdrag the center x handle to move the Spiral. Note the x handle may be hidden under the center diamond handle.

Modify a spiral object with keyboard

The cursor (arrow) keys can be used to move selected handles horizontally and vertically.

• Press AltOption + arrow for small adjustments. Zoom in for even finer adjustments.

• Press Shift + arrow for large adjustments.

See also

For more detail on using the AltOption and Shift modifier keys, see Transformations Section.

Warning

Adjustments made with the arrow keys fail to update the XML file. Also the Tool control bar Turns and Inner Radius entry boxes fail to change.

Work around:

Switch to the Selection tool and move the spiral one arrow keypress and then back again. This forces the entry boxes and XML to update.

• With a spiral selected the [ or ] key will rotate the spiral in 15° steps.

• The < (,) or > (.) key will shrink/enlarge a spiral (See Transformations Section ).

Note

With multiple objects selected, the keys will rotate and resize around the center of the selection area.

Tool controls bar

• Turns: Number of turns (revolutions) of the spiral path

• Divergence: Spacing between the spiral turns

• Inner Radius: Unwind/Rewind the inner turns from the center

• Restore to the default: Turns=3, Divergence=1, InnerRadius=0

Entry box arithmetic (+ add, - subtract , * multiply , / divide) is possible. Computation progresses from left to right.

Understanding Spiral Divergence:

Divergence describes how quickly the radius of a spiral changes as the angle increases. It reflects the rate at which the spiral expands or contracts with each turn.

• A divergence of 1 produces a uniformly spaced spiral — also known as an Archimedes’ spiral — where the gap between successive turns stays consistent.

• Divergence less than 1 results in a spiral that tightens as it progresses outward, with decreasing distances between the coils.

• Divergence greater than 1 leads to a spiral that loosens, expanding outward with increasing gaps between turns.

Adjustments with Object Properties dialog

Todo

revisit this part at a later point when the Object Properties chapter is done. (No object properties currently)

With the Selection tool enabled

The spiral can be modified using the transformation handles (See Object Transformations).

With Node tool and other shape tools enabled

The same handles are available as with the spiral tool enabled.

Note

When multiple shape objects are selected only the Node tool will display the modification handles.

Modify/view with XML Editor

Example Spiral

Name	Value	Units in mm (millimetres)
inkscape:transform-center-y	-1.4075964
inkscape:transform-center-x	-1.4083655
d	M 0.29974154,0.29974267 C…	SVG path
sodipodi:t0	0.081973173	inner radius
sodipodi:argument	-11.644569	angle of end pt.?
sodipodi:radius	19.654741
sodipodi:revolution	1.7878424	number of turns
sodipodi:expansion	0.35795671	divergence
sodipodi:cy	0.29974267	spiral center point
sodipodi:cx	0.29974154
id	path5
style	fill: none;…..	CSS style properties
sodipodi:type	spiral

In Inkscape, the Spiral tool utilizes Sodipodi attributes to define spiral properties, particularly for parameters like the number of turns, radius and divergence. These parameters are stored using XML attributes prefixed with sodipodi: and inkscape: within the Inkscape SVG code.

When the SVG is reloaded into Inkscape these attributes are used to regenerate the SVG path d=”” attributes.

If exported as Plain SVG only the path will be saved (same as if applied Object to Path), if then reloaded into Inkscape the spiral will no longer be editable using the Spiral tool.

Todo

Examples{link} using spiral tool

Fill/gradient (odd/even)