Symmetric Shapes
A shape can have symmetry added to it using the Path Symmetry submenu. This provides the following menu items:
- If this menu item is selected, symmetry will be added to the path.
For example, Figure 8.7(a) shows a path in edit mode, and Figure 8.7(b) shows the
path with symmetry applied to it. There are now two extra
control points (coloured blue). These points govern the line
of symmetry8.2. In Figure 8.7(c), these two controls
have been moved.
If you later decide to remove the symmetry, deselect .
Adding symmetry to a closed shape may cause unexpected
results as the shape will be first opened (without removing the
last segment), the symmetry will be added, and then the symmetric
shape will be closed, merging the end points.
- When you add symmetry to a path, the final control point of the
underlying path is anchored to the line of symmetry. That is, it
can only move along the line defined by the two blue
control points. To remove the constraint, deselect this menu
item. In Figure 8.7(d), the end anchor item has been
deselected, and the end control moved away from the line of
symmetry.
Note that this function places a gap (move) segment between the end control and its symmetric counterpart. This can be changed to a line or curve, using Convert To Line or Convert To Curve, as described in Editing Control Points. In Figure 8.7(e), the join has been changed to a curve. Unlike the Bézier curves in the non-symmetric paths, this curve only has one curvature control.
- This menu item is only available for closed symmetric paths. A closed symmetric path by default has its first control point anchored to the line of symmetry. Deselect this menu item to remove the constraint. For example, Figure 8.8(a) shows a closed symmetric path (a closed version of Figure 8.7(e)). The anchor on the first control was then removed and the control was moved to the left (Figure 8.8(b)). As with the join segment (above) the gap segment between the start control and its reflect can be changed to a line or curve. As above, the curve only has one curvature control (Figure 8.8(c)).
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See also:
Footnotes
- ... symmetry8.2
- The line of symmetry extends infinitely though the two controls, but only the part of the line between the two points is actually displayed in edit mode.