While extending a path, a number of keys may be pressed to change preferences on the fly or change functionality. As with all Astute tool keypresses, these will be indicated on the Astute Buddy panel.

Command/Ctrl: Overrides any snapping or constraining that is in effect.

Space: Hides the annotations.

Up Arrow/Down Arrow: Changes the spiral winding constant.

Left Arrow/Right Arrow: Changes the fixed radius value (when in Fixed radius mode) or the radius scale factor (when in Scaled radius mode).

A: Toggles the Extend All Selected Open Paths preference.

C: Toggles the Constrain Length by Multiples preference.

E: Cycles through the four extension modes (Single Bezier, Constant Radius, Straight, and Spiral).

H: Changes the annotation color (red by default).

I: Toggles the Calculate Intersections preference. When extending paths over very complex artwork, pre-calculating all the possible intersections may cause a noticeable delay in extending the path.

L: Toggles the Show Length preference.

M: Switches the measurement mode between absolute and percentage.

O & P: When extending multiple paths, changes the maximum random variation value (0% to 100%).

Q: When extending multiple paths, toggles the randomization mode.

R: Cycles through the three radius submodes (Matched, Scaled, and Fixed).

S: When extending multiple paths, changes the random seed. This produces a different randomly chosen variation value for each path.

U: Temporarily disables Smart Guides, if they were enabled when the drag started.

V: Toggles the curvature type. Normally the curvature of the extension is in the same direction as the existing path; Reverse Curvature makes the extension curve in the opposite direction:

Extend Path Keypress Reverse extension curving

Extend Path Keypress Reverse extension curving

X: Manually locks and unlocks the extension type. Because the forward and backward extensions can sometimes overlap, locking the extension (for example, so the path can only be lengthened in the forward direction) can keep the cursor from “jumping” to the other extension and causing the path to be reverse extended. The extension type is automatically locked based on the initial drag direction and automatically unlocked if the cursor is passed near to the original endpoint from which the drag started.

Z: Switches the starting endpoint. This can be useful if the original endpoints of the open path were very close together and the opposite endpoint was the desired one.