3D curve drawing is a fundamental operation in the creation and manipulation of surfaces and 3D models. Although techniques for specifying 3D curves using 2D input devices have been developed extensively, they are mostly indirect, with the need of multiple viewpoints or multiple lines to specify a 3D curve. We propose a simple technique to directly specify a 3D curve - using pen pressure to draw a single line of varying thickness, and mapping the thickness at each point along the curve to a depth distance. Hence, the thicker the 2D curve at a particular point, the closer the corresponding 3D point to the camera. This method is easy and intuitive, and yet surprisingly it has not been reported before. We illustrate the effectiveness of the method with numerous examples. © 2010 Springer-Verlag Berlin Heidelberg.