Hold down
+
(Windows) or
+
(Mac), click the curve and drag along the curve.
When you are sketching, you can snap a brush to a curve (or surface isoparametric curve or curve-on-surface). This allows you to use curves as sketching guidelines.

button to the right of the prompt line, or hold down
+
(Windows) or
+
(Mac), to activate curve snapping.
The brush profile will jump onto the curve.
To set the brush curve snap tolerance, choose Preferences > General Preferences
❒, then choose Paint from the left side of the option window, and set Brush Curve Snap Tolerance to the number of pixels the brush cursor must be from a curve in order for the brush profile to jump onto the curve.
button again, or release
+
(Windows) or
+
(Mac), to de-activate curve snapping.
You can snap to invisible curves (see ObjectDisplay > Invisible
) or curves on invisible layers (Layers > Visibility > Invisible
).