6.3 Mouse Control in the Viewer Window

The Viewer's mouse controls are extensive and flexible. The resulting action depends on the choice of mouse button, how the mouse is moved and simultaneously pressed control keys. The descriptions in Tables 6.1 and 6.2 may seem complicated, but with practice, use of the mouse becomes intuitive.

Table 6.1: Mouse controls for the Viewer

Mouse Controls
Control Key	Button	Action
None	Left	Translate scene
	Middle	Rotate scene about its center on an arc ball that surrounds it; rotation direction is a function of the initial mouse location so try different sites and note the response.
	Right	Zoom or scale scene (downwards and to the right increases size, upwards or to the left decreases size)
Shift	Left	Select and move a widget in the display
	Middle	Toggle through the modes for a widget
	Right	Pop up a widget information window
Control	Left	Translate in the Z-direction, i.e., zoom in and out of the screen (down moves closer, up further away). Moving left and right increases the ``throttle'' of the Z-direction motion. If the cursor is over a point on an object when clicked, this point becomes the center of the screen for translation.
	Middle	Rotate the camera view about the eye point (using arcball motion).
	Right	Unicam movement (see Table 6.2)

Table 6.2: Autocam mouse controls in the Viewer

Unicam movement (Control key and right mouse button
Initial mouse location	Action
Near edge of display	Rotate objects on the arc ball
Near the objects	Following behavior:
	Initial mouse movement	Action
	Horizontal	Pan objects
	Vertical	Zoom and pan: down = zoom in, up = zoom out, left and right= pan left and right)
	None	Set rotation point for subsequent arc ball rotation.