AzEl Mask Tool
The AzEl Mask tool generates static body masking files (.bmsk) which are used to restrict visibility to a sensor. The term body masking refers to line of sight obstruction caused by the three dimensional model of the parent object of the sensor or other objects in the scenario. The body masking files contain obscuration contours which are generated based on six views generated from the point of view of an observer at the location of the sensor. The six views can be thought of as containing projections of the obscuration objects onto the faces of a cube centered at the sensor. Contours are constructed using an edge detection algorithm and stored along with information describing the orientation of the view from which they were constructed. To affect visibility computations, set the body masking file as the AzEl Mask file for the sensor, and enable the sensor AzEl.
To access the AzEl Mask tool for a particular sensor, highlight the sensor in the Object Browser and select AzEl Mask... from the Sensor menu.
To get a quick overview on how the AzElMAsk tool works, see Using the STK AzEl Mask Tool.
The .bmsk file cannot be computed if the graphics window is integrated. It must be a floating window. To set the graphics window to floating, right-click the graphics window title bar and select Floating from the list menu.
The AzEl Mask tool contains:
- Az/El Mask View window. This window allows you to see the obscuring objects in the six views used in generating the contours. The views will be shown in successive fashion when the Compute button is clicked. Use the
button on the Default toolbar to access the AzEl Mask window. - AzEl Mask window. This window enables you to identify obscuring objects and define the instant in time at which obscuration contours are computed. The time at which obscuration contours are computed is independent of the current animation time and may be important in cases where the parent body has articulating parts or if objects other than the sensor parent body are considered as obstructions.
You cannot use the AzEl Mask tool on any model that contains the FaceEmissionColor parameter.
Obscuring Objects
The Obscuring Objects list contains the central bodies and scenario objects that are candidates for obscuring the sensor's field of view. Stars and planets, except for the central body, are excluded from the list. Any or all of the available objects can be selected for analysis.
The central body will be rendered as part of the mask, and it includes terrain.
Select All button. Selects all items in the Obscuring Objects list.
Deselect All button. Clears all items in the Obscuring Objects list.
You can also use the mouse to select individual items in the Obscuring Objects list.
Data
Use to specify various parameters used to generate a body mask file.
Time. The animation time for which the mask is generated. This time determines the state of any articulations of models for objects selected as obscuring objects.
File. The name of the body mask output file (.bmsk). This file can then be loaded through the AzEl page of the sensor's Basic properties.
Window Dim. The height and width, in pixels, of the window used to generate the body mask. Larger window sites produce more accurate masks which require more access computation time.
A mask file cannot be generated if the window dimensions are too small or larger than the STK workspace.
Rendering
Do not render normal 3D windows while computing. Select to stop rendering normal 3D Graphics windows when the tool is computing data. This option can improve the speed of the computations.