Frame 4

You may modify the viewpoint from which the project geometry is visualized in an 'Animation View' window by

1. Zooming in and out relative to the current focal point.
2. Rotating the current focal direction.

To zoom relative to the current focal point

1. Make sure the 'Rotate and Zoom' icon in the camera toolbar is disabled by clicking on it if necessary;
   
   =disabled =enabled
2. Press down the right mouse button somewhere in the window;
3. Move the mouse in the vertical direction;
4. Release the right mouse button when you have achieved the desired degree of zoom.

To rotate the current focal direction

1. Make sure the 'Rotate and Zoom' icon in the camera toolbar is disabled by clicking on it if necessary;
   
   =disabled =enabled
2. Press down the left mouse button somewhere in the window;
3. Move the mouse in the vertical and/or horizontal directions;
4. Release the left mouse button when you have achieved the desired focal direction.

When you press down the left mouse button in an 'Animation View' window, a red arrow, a green arrow, and a blue arrow appear in the center of the view. These arrows emanate from the current focal point and correspond to the one-, two-, and three-direction, respectively, of the world reference triad.

The current focal direction is determined by two angles corresponding to the latitude and longitude of a point on a sphere centered on the focal point and with north-south axis parallel to the three-direction of the world reference triad.

Moving the mouse in the horizontal direction with the left mouse button pressed down changes the value of the longitudinal angle. Moving the mouse in the vertical direction with the left mouse button pressed down changes the value of the latitudinal angle.

The horizontal direction in an ‘Animation View' window is always parallel to the plane spanned by the one- and two-directions of the world reference triad. Consequently, the endpoint of the blue arrow representing the three-direction of the world reference triad always lies on the vertical line through the center of an 'Animation View' window.

The default viewpoint is one for which the focal direction coincides with the three-direction of the world reference triad and the vertical direction is parallel to the two-direction of the world reference triad.

At any time, you may return to the default viewpoint by clicking on the ‘Reset camera' icon in the camera toolbar.

Frame 4