View Path Editor
Use the View Path Editor (
) to maintain view paths created using an earlier version of STK. Starting with STK 6.0, the Camera Control tool replaces the View Path Editor for creating view paths (now called camera paths).
Using the View Path Editor, you can store a camera position and view data at a user-defined animation time. This stored camera position and time is defined as a key frame. A sequence of key frames is called a view path. A view path can be replayed and followed during animation. Depending on the animation time step and the time step between key frames, STK interpolates using splines to determine views between key frames. View paths, therefore, tend to transition smoothly from key frame to key frame. Using the Record Movie capability, each frame generated while animating along a view path can be written to a file. These files can then be used to create movies or videos.
STK supports multiple view paths per window, though only one is active at any time. Only the current view path can be edited and followed in the 3D window. The current view path is displayed in the 3D window with its key frames drawn as points. All other view paths do not display individual key frames. View paths are displayed as smooth lines that a camera's viewer position follows during animation while following a view path. The camera's "pointing," or viewer direction, data is not shown explicitly, although the current look and up vector can be shown on the rendered view path.
When rendered, the current view path's key frames are drawn as points along the view path. Only one of these key frames, called the current key frame, can be modified at one time. This key frame is drawn as a point three times larger than all other key frames on the current view path. The View Path Editor can be used to create, modify, or remove the current key frame. The current view path is the path being edited. When multiple paths are displayed, the current path is the only one whose key frames are rendered as points.
Path
The Path table shows a summary of all available view paths and their display attributes. You can rename an existing view path, edit the key frames that make up a path, or change the display of the path in the 3D window.
Name. Name of the view path. Double-click it to make it editable.
Color. Color of the view path line.
New button. Creates a new view path with a default name of ViewPath followed by a sequential identifier that indicates the number of unnamed view paths in the table (e.g., ViewPath0, ViewPath1, ViewPath2, etc.).
Duplicate button. Duplicates the selected view path. The duplicated view path name is the name of the path that was duplicated followed by the word Copy and a sequential identifier that indicates the number of unnamed copies of that path (e.g., ViewPath0Copy0 or ViewPath1Copy0). If you have a situation that requires similar view paths, duplicating and editing an existing view path may save you some time. You can rename the view path by double-clicking it and entering a new name.
If you do not change any of the key frames or path attributes of a duplicated path, it will not be visible in the 3D window. The two paths will be identical making their displays overlap and appear to be one path.
Delete button. Deletes the selected view path.
Key Frames
A key frame is a record of the viewer position, viewer direction and the direction of the up vector at a given time. Each frame is stored as an X, Y, Z position in inertial space. You can change the view in the 3D window at any time to the current key frame by double-clicking a key frame in the Key Frame table. The viewer direction, viewer position, and time are then changed to that of the selected key frame. In addition, the current animation time and time step are changed to the values used when the key frame was saved.
Frame #. Sequential index for each key frame in the current view path
When you create a key frame the current view, including viewer position, direction and current animation time, is stored in the currently selected view path. The new key frame is added to the Key Frame table directly after whichever key frame is selected in the table. The new key frame then becomes the current key frame. STK then incrementally increases the current scenario animation time according to the animation time step set, so that another key frame can be added without having to increment the current time.
Time. Sequential time for each key frame in the current view path.
All key frame animation times within a given view path must be in increasing order for the view path to be valid.
Add button. Adds a key frame using the animation time and view set in the 3D Graphics window for the selected view path. Use the mouse and Animation controls to set the view and animation time in the 3D window exactly as you want it to be added as a key frame.
You can use the 
button to quickly add key frames without opening the View Path Editor.
Delete button. Deletes the selected key frame from the Key Frames table.
Modify button. Modifies the selected key frame for an existing view path using the animation time and view set in the 3D Graphics window. Double-click a view path to display its key frames. Use the mouse and Animation controls to set the view and animation time in the 3D window exactly as you want the key frame to be modified.
When you select a key frame from the table in the Key Frames area, the point representing that key frame will be three times larger than the points representing other key frames along the view path.
Clear button. Clears all key frames from the selected view path.
Path Attributes
Use to customize the display of a selected view path.
Follow path while animating. Uses the current view path for view data while animating. When this option is selected, you cannot use the mouse to change the current view in the 3D Graphics window.
Type. Specifies the path type:
Splined. The animation follows the view path spline for all viewer position and viewer direction positions of the stored key frames.
Tethered. Camera is attached to object and follows view path. Object is always at the center of the frame. To change the distance between the camera and the object, move the viewer position closer to the object.
Auto-smooth path. If selected, corrects for anomalies in object motion by optimizing the smoothness of the path between key frames.
Great Arc vehicles (ships, aircraft, and ground vehicles) or vehicles using an external ephemeris file sometimes follow an irregular path which may cause jitter problems when creating videos. When you enable the Auto-smooth path feature, STK automatically smooths the view path--the camera position and direction are adjusted to compensate for irregular vehicle motion between key frames. If the object seems to bounce along the view path, there may be too many changes in position or direction between key frames. Check the shape of the curve between the key frames of interest to determine if this is true. To avoid issues such as this, try to keep the distance between key frames the same.
To create a smooth view path that travels completely around an object, use at least five key frames.
Show Up/Look Vectors. If selected, displays Up and Look vectors for current view path when animating. The vectors are displayed on the view path at the camera location for the current animation time.
Scale. If selected, use the text box or slider to resize to exponentially scale the size of the vectors.