Easy Orbit in 3d DWF's

These key combintations greatly simplify orbit when viewing 3d Dwfs. This is covered in the DWF Viewer Help but took me a while to notice. Using your mouse, you can rotate the 3D Orbit view in the following ways:
Freely Rotating the View
When you move the cursor inside the viewing area, it changes to a small sphere encircled by two lines. If you click and drag, you can move freely around the objects. It works as if your cursor were grabbing a sphere surrounding the objects and dragging it around the target point. You can drag horizontally, vertically, and diagonally using this method.
Rotating the View Horizontally
If you hold the shift key down while dragging, the cursor becomes a horizontal ellipse. Clicking and dragging when the cursor is a horizontal ellipse rotates the view around a vertical axis through the middle of the object or model.
Rotating the View Vertically
If you hold the CTRL key down while dragging, the cursor becomes a vertical ellipse. Clicking and dragging when the cursor is a vertical ellipse rotates the view around a horizontal axis that extends through the center of the object or model.
Rotating the View in a Roll
If you hold both the CTRL and shift keys down while dragging, the cursor becomes a circular arrow. Clicking when the cursor is a circular arrow causes the view to move around an axis that extends through the center of the arcball, perpendicular to the screen. This is called a roll.