1) ...videotape

The videotape can be obtained upon request from the authors.

2) ...mouse

We think that a tablet/pen and an active LCD screen implementation might be even better. See Section 6.

3) ...plane

A plane perpendicular to the view direction and close enough to the eyepoint not to interfere with the objects in the scene.

4) ...1).

If the ray intersects no surface (possible because we use a finite ground rectangle instead of an infinite ground plane), the object is placed in the plane perpendicular to the view direction that passes through the origin; this turns out in practice to be a reasonable compromise.

5) ...key.

Recall from Table 1 that Shift-modified strokes normally produce lines drawn on the surface of objects without special interpretation.

6) ...2).

The lasso gesture is similar to the sphere gesture. We differentiate between them by requiring that the sphere gesture be followed by a dot stroke, whereas the lasso is simply a free-hand closed curve stroke followed by a manipulation gesture.