Set 3D View

Click the View menu > Set 3D View command or the

toolbar button to access the Set 3D View form and set the window to a three-dimensional (3D) view. Use the Set 3D View form to define the View Direction Angle by specifying a plan angle, elevation angle and an aperture angle. All angles are specified in degrees. The view direction defines the location from which an observer would view the building from the outside (see Figure).

Fast View buttons. The 3D View form has four fast view buttons labeled 3d, xy, xz and yz. The fast view buttons automatically set the plan, elevation and aperture angle to give the specified 3D view.

Figure "a" below shows a three dimensional view of a building using the default view direction of plan angle = 225 degrees, elevation angle = 35 degrees and aperture angle = 60 degrees. Figures b, c and d illustrate how the plan, elevation and aperture angles are defined. Following the figure are definitions of the terms used in the figure.

- Eye point: This is the location from which an observed would be viewing the building.
- Target point: This is the geometric center of the building.
- View direction: This is defined by a line drawn from the eye point to the target point.
- Plan angle: This is the angle (in degrees) from the positive global X-axis to the line defining the view direction measured in the horizontal global XY plane. A positive angle appears counterclockwise as you look down on the model. Any value between -360 degrees and +360 degrees, inclusive, is allowed for the plan angle.
- Elevation angle: This is the angle (in degrees) from the global XY plane to the line defining the view direction. A positive angle starts from the global XY plane and proceeds toward the positive global Z-axis. A negative angle starts from the global XY plane and proceeds toward the negative global Z-axis. Any value between -360 degrees and +360 degrees, inclusive, is allowed for the elevation angle.
- Aperture angle: The plan angle and the elevation angle together define the direction from the eye point to the target point. The aperture angle sets the distance from the eye point to the target point. This distance is set as follows:
- - The program constructs the view direction line from the eye point to the target point.
  - The program constructs a 3D bounding rectangular box that just encloses the model.
  - The program passes a plane through the target point and perpendicular to the view direction line.
  - The program projects the eight corner points of the bounding box onto the plane. Call these the projected corner points.
  - The program constructs lines from the eye point to the projected corner points of the bounding box. Eight such lines are constructed because there are eight corner points. Call these eight lines corner point lines.
  - The program locates the eye point along the view direction line such that the largest angle between the view direction line and any of the eight corner point lines is equal to one-half of the specified aperture angle. This ensures that the entire structure is included in the view. Note that the program does not allow the eye point to be located inside the structure.

Note: Clicking the

3D View tool button gives the default 3D view, with the plan, elevation and aperture angle as specified in the figure above.

When the active window is showing a 3D view, click the

Rotate 3D View toobar button and use the mouse to adjust the view direction. After the button is clicked, left click the mouse in the window with the 3D view and while holding down the mouse left button, drag the mouse to adjust the view direction. Note that as soon as the mouse is left clicked in the window with the 3D view, a bounding box (dashed lines enclosing the model) appears and that as the mouse is dragged, the orientation of the bounding box changes, showing the new orientation of the model. When the left mouse is released, the entire model is redrawn in the new view direction.

Set 3D View (Three Dimensional)