STK/VO Standard Tutorial
CONTENTS OVERVIEW ............................................................................................................2 SETTING UP...........................................................................................................3 USING THE MOUSE IN THE 3D GRAPHICS WINDOW .............................................6 PROPERTIES SETTINGS IN THE 3D GRAPHICS WINDOW..........................................9 SETTING THE DISPLAY OF A SENSOR....................................................................17 USING THE 3D OBJECT EDITOR...........................................................................20 WORKING WITH THE 3D GRAPHICS TOOLBAR – MANAGING VIEWS ....................22 DISPLAYING AND MODIFYING A MODEL .............................................................27 MOVING ONWARD .............................................................................................32
STK/VO Standard Tutorial
2 of 32
Overview The Visualization Option (VO) module for STK is a dynamic 3D visualization environment that displays scenario information from the STK software suite. This powerful tool provides an intuitive view of complex mission and orbit geometries by displaying realistic 3D views of space, airborne, and terrestrial assets, sensor projections, orbit trajectories, or assorted visual cues and analysis aids. STK/VO provides state-of-the-art interactive graphics performance, driven by precise, validated and verified numerical data derived from the STK geometry engine. The STK/VO Standard Tutorial explores the power and possibilities of STK’s 3D graphics module. In the exercises that follow, you will learn about some of the many properties settings that can define a 3D Graphics window, and the 3D visualization options of objects within a scenario. You will also learn about manipulating, setting, and storing views, editing objects within the 3D Graphics window, and working with models.
NOTE: This tutorial is intended for users with at least a basic understanding of the STK interface. If you are unfamiliar with the process of creating and defining scenarios and objects, you should first work through a tutorial on the basics of STK before proceeding with this tutorial.
STK/VO Standard Tutorial
3 of 32
Setting Up Before you begin to explore the VO module, you need to build a scenario that we can study with it. 1. Create a new scenario and name it “VOTools”. 2. In the Properties Browser for the scenario, select Basic - Time Period and set the options to the values shown here:
3. Select Basic - Animation and set the options to the values shown here:
4. Create a satellite and name it “LEO”. 5. If the Orbit Wizard appears, click Cancel. 6. In the Properties Browser for the satellite, select Basic - Orbit and set the options to the values shown here:
STK/VO Standard Tutorial
4 of 32
7. Create a facility and name it “DC”. 8. In the Properties Browser for the facility, select Basic - Position and set the options to the values shown here:
9. Create a sensor attached to the LEO satellite and name it “LOOK”. 10. In the Properties Browser for the sensor, select Basic - Definition and set the options to the values shown here:
STK/VO Standard Tutorial
11. Click Reset
in the Animation toolbar.
12. Save the scenario.
5 of 32
STK/VO Standard Tutorial
6 of 32
Using the Mouse in the 3D Graphics Window The perspective of the 3D Graphics window is defined by three components: camera position, camera reference point, and view direction. The camera position is the location from which you are looking and the camera reference point is the object at which the camera is pointing. The view direction is the direction vector from the camera position to the camera reference point. By default, the camera reference point is the center of the Earth and the camera position is 52,780 kilometers above Mexico. In the representational image below, the view direction is depicted as a line between the camera position and the camera reference point.
You can manipulate the view in the 3D Graphics window in three ways: you can sweep the camera position, sweep the camera reference point, and zoom. The following table outlines how you can manipulate views in the 3D Graphics window using the mouse: Mouse Button
Movement
Left
Sweeps the camera position with respect to the camera reference point.
Right
Zooms the camera position in and out with respect to the camera reference point.
Shift + Left
Sweeps the camera reference point with respect to the camera position.
Ctrl + Right
Undoes a movement of the camera reference point resulting from Shift + Left interaction.
Ctrl + Left
Locks horizontal movement so that you can sweep the camera position vertically without accidentally altering your horizontal axis.
Alt + Left
Locks vertical movement so that you can sweep the camera position horizontally without accidentally altering your vertical axis.
STK/VO Standard Tutorial
7 of 32
You can also zoom by clicking the Zoom In button in the Default toolbar and then clicking and dragging over the area within the 3D Graphics window that you wish to magnify. The camera will zoom in on the selected area, and the camera reference point will be set to the center of the zoom area. The representational images below show the effect of sweeping the camera position about the camera reference point (the left image), and of sweeping the camera reference point about the camera position (the right image). When sweeping the camera position, you can see that the camera is now in a different location than in the first image, above. The original position is off to the left, following the view direction line. When sweeping the camera reference point, the camera remains in place, but is adjusted to pinpoint a different spot within the 3D Graphics window; the original reference point is no longer the center of your view.
The representational image below shows how the view is magnified when you zoom in on the camera reference point.
STK/VO Standard Tutorial
8 of 32
Before proceeding with the tutorial, take some time to experiment with using the mouse to control the view in the 3D Graphics window.
STK/VO Standard Tutorial
9 of 32
Properties Settings in the 3D Graphics Window In this exercise, you will explore some of the properties that can be specified for the 3D Graphics window. There are far too many settings to examine in a tutorial, so you will focus on a selection of some of the most frequently used properties. To begin, follow these steps to arrange STK in the most suitable manner for this exercise. 1. In the STK workspace, select the 3D Graphics window and click Properties toolbar to display the 3D Graphics properties window.
in the Default
2. Once the 3D Graphics properties window has appeared in the workspace, try to separate it from the 3D Graphics window as much as possible, so that you can easily and quickly view any changes you make to the properties. Depending on the size of your monitor and the resolution setting of your Windows desktop, you may want to release one or both of the windows from the confines of the STK workspace. Right-click on the window’s title bar and select Floating from the drop-down menu to give yourself the freedom to move the windows anywhere on the screen. When moving the windows, hold down the Ctrl key to prevent the windows from “docking” with another part of the application. Once you are comfortable with the arrangement of these two windows, click on the 3D Graphics properties window to continue with this section of the tutorial.
3. In the 3D Graphics properties window, click on the properties page names as follows to get an overview of some of the most commonly used settings in the 3D Graphics properties browser.
Globe The first page of the 3D Graphics properties window is the Globe page. This page contains settings for the surface texture of the globe, the appearance of clouds, and defining the primary
STK/VO Standard Tutorial
10 of 32
body – the Earth by default. Note that changing the primary body of the 3D Graphics window does not change the primary body of your scenario – follow these steps for an illustration of this point: 1. Select Mars as the Primary Body in the Central Body frame and click Apply. 2. Notice that in the 3D Graphics window, the view switches to a view centered on Mars. The objects of your scenario, however, remain in their defined positions around or on the Earth.
3. Re-select Earth as the Primary Body and click Apply. The Globe File Editor… button located at the bottom of the page allows you to make modifications to the globe file being used. If, for instance, you had a high-resolution image of the area around the DC facility, you could edit the globe file to include that image as a part of the globe.
Details The Details page contains settings for the display of a number of delimiters, from international borders to latitude and longitude lines. For example: 1. Enable Show in the Map Details frame. Select International Borders and click Apply. 2. National borders now appear on the face of the globe.
STK/VO Standard Tutorial
11 of 32
3. Disable Show and click Apply. The Show Location of 2D Maps feature, when enabled, displays an outline of the boundaries of the 2D Graphics window view when you have zoomed in on a feature or region on that map. For example: 4. Enable Show Location of 2D Maps in the 2D Map Zoom frame and click Apply. 5. Select the 2D Graphics window, and then click Zoom In
on the Default toolbar.
6. Click and drag over the eastern United States to zoom the map in to a closer view of the DC facility. 7. Select the 3D Graphics window and rotate the globe so that North America comes into view. Notice that the area that is magnified on the 2D map is framed on the globe.
8. Disable Show Location of 2D Maps and click Apply.
STK/VO Standard Tutorial
12 of 32
Celestial The Celestial page contains settings for the display of celestial bodies within the 3D Graphics window. Choosing to display a celestial body from this page places a reference marker for the body in the context of the 3D Graphics window; it does not create the celestial body as an object in your scenario. There are also several settings related to the Sun that can be controlled on this page. For example: 1. In the Sun frame, enable Show Umbra Cone and click Apply. 2. The umbra cone is now displayed, showing the shadow cast by the Earth. Objects within that cone are completely blocked from the Sun.
3. Disable Show Umbra Cone and click Apply.
Lighting The Lighting page contains a number of settings that play important roles in the visualization of your scenario. In the Sun Lighting frame, the appearance of sunlight can be modified with respect to the globe and independently with respect to objects in the scenario. The Other Light Sources frame is comprised of controls to create and manipulate user-defined light sources within the 3D Graphics window. For example: One way to illuminate the entire globe is to disable Enable Lighting, which turns off all the lighting controls. Doing this however, leaves you with no distinction between what is actually being illuminated by the sun and what isn’t. Instead, you can define a user controlled light source to ensure that the entire globe is illuminated while leaving the difference between what part of the Earth is in daylight and what part is in darkness discernable. 1. In the Other Light Sources frame, click New. A light source named “LightSrc0” will appear in the list of light sources. 2. Set the Type to Directional. 3. In the Position/Direction frame, click Select… next to the Direction: field.
STK/VO Standard Tutorial
13 of 32
4. Expand the selections under Earth, select Sun, and click Close. 5. In the Level frame, manually enter 350.0 as the value; this will match the default magnitude of the Sun. 6. Verify that the color of the light is bright green, or some other bright, pale color that will illuminate without washing out everything it touches, and click Apply.
7. Looking at the 3D Graphics window, you will notice that the area of the Earth that is in the Earth’s shadow is now illuminated by a light of whichever color you selected. The entire globe is now illuminated for better visibility, yet at a glance you can tell where daylight begins and ends.
STK/VO Standard Tutorial
14 of 32
8. In the Other Light Sources frame, click Delete, and then click Apply.
Grids The Grids page contains settings for different frame of reference grids that can help make the 3D Graphics window of a scenario more visually informative. For example: 1. In the Ecliptic Coordinates frame, enable Show, and click Apply. 2. The Ecliptic Coordinates space grid is now displayed in the 3D Graphics window, with the Earth as its epicenter. The Ecliptic Coordinates grid represents the plane within which most of the planets of our solar system orbit the Sun.
STK/VO Standard Tutorial
15 of 32
3. Disable the Ecliptic Coordinates grid and click Apply.
Lines The Lines page allows you to set lines to be rendered between objects in the scenario. The Display Times button gives you the option to have a line display in different colors over time within the scenario. The line will change color during the animation at the times that you specify. For example: 1. Select the LEO satellite in the From frame and the DC facility in the To frame. 2. Click the right-arrow button
to set a line between the objects.
3. Click Display Times. 4. In the Display field, select Use Intervals. 5. Click Add to create the following new intervals:
6. Enable Use Color for each interval and change the colors so that they are not the same. 7. Click OK to close the Display Times window and then click Apply on the Lines page. 8. Animate the scenario and observe that the line color changes according to the intervals you established.
STK/VO Standard Tutorial
9. Remove the line by clicking the left-arrow button
16 of 32
on the Lines page, and then click Apply.
10. Reset the Animation, and click OK to close the 3D Graphics properties window.
And more… These exercises have only scratched the surface of the many ways in which you can set and alter properties in the 3D Graphics window. Please consult STK Help for more information regarding the properties settings of the 3D Graphics window.
STK/VO Standard Tutorial
17 of 32
Setting the Display of a Sensor In addition to the environmental properties of the 3D Graphics window, every object in a scenario has 3D graphical properties that can be customized. The exercise in this section demonstrates how to display a projection of a satellite’s sensor to enhance the visualization of your scenario. 1. Open the Properties Browser for the LOOK sensor. 2. Select 3D Graphics - Attributes.
3. Enable Translucent Lines. 4. Select 3D Graphics - Pulse. 5. In the Parameters frame, enable Show, and set the options to the values shown here:
STK/VO Standard Tutorial
18 of 32
6. Click OK. 7. Click View Position and Direction
on the 3D Graphics Toolbar.
8. In the View From field, select the LEO satellite. The LEO satellite will also become highlighted in the View To field. Click OK. 9. In the 3D Graphics window, adjust the view so that you can get a good look at the satellite in reference to the Earth’s surface, such as the following image depicts.
STK/VO Standard Tutorial
19 of 32
10. Animate the scenario and watch the sensor’s projection as the satellite travels along its orbit. 11. Reset the animation. 12. Click Home View
on the 3D Graphics Toolbar to set your view to the default position
STK/VO Standard Tutorial
20 of 32
Using the 3D Object Editor Facilities, area targets, and great arc vehicles can have their boundaries or routes edited directly within the 3D Graphics window using the 3D Object Editor. This exercise explores the basics of using the 3D Object Editor. 1. Create an area target and name it “Sahara”. Set the boundaries of the Sahara area target with the following points:
2. Manipulate the view in the 3D Graphics window so that the Sahara area target is roughly centered. 3. In the View menu, select the 3D Object Editing toolbar. 4. In the 3D Object Editing toolbar, select the Sahara area target from the drop-down menu.
5. Click Object Edit Start/Accept to begin editing the Sahara area target in the 3D Graphics window. The boundary points of the Sahara area target are now highlighted in the 3D Graphics window.
STK/VO Standard Tutorial
21 of 32
6. By clicking and dragging with the mouse, expand the Sahara area target’s boundaries to encompass the entire desert region of northern Africa. Notice that while editing the object, the usual mouse controls for manipulating the view in the 3D Graphics window function normally. 7. Click Object Edit Start/Accept boundaries.
to apply the changes. The area target now has new
8. You can cancel the 3D Object Editor by clicking Object Edit Cancel not already accepted the changes. 9. Delete the Sahara area target before proceeding with the tutorial.
at any time, if you have
STK/VO Standard Tutorial
22 of 32
Working with the 3D Graphics Toolbar – Managing Views In this exercise, you will learn to establish custom views that will be more useful or appealing than the default view. The default view in the 3D Graphics window, called the Home View, is an Earth-centered inertial position and direction. You can change the Home View and add other views in the 3D Graphics window using the 3D Graphics Toolbar. The ability to change the camera position and the view direction or camera reference point can be very helpful in analyzing a scenario. When you create and store a view, the view is a part of the scenario and can be utilized in any number of 3D Graphics windows that you open within the scenario. The following steps will guide you through the basics of setting and storing views in the VO module. 1. Click Home View
on the 3D Graphics Toolbar to set your view to the default position.
2. Animate the scenario. Notice that during the animation we cannot see our DC facility for the entire time. As the Earth rotates, the DC facility comes into view for only a limited portion of the animation period. 3. Reset the animation. 4. Click View Position and Direction
on the 3D Graphics Toolbar.
STK/VO Standard Tutorial
5. In the Reference Frame section, select Earth Fixed Axes and click OK. 6. In the 3D Graphics window, rotate the view so that the DC facility is roughly centered.
23 of 32
STK/VO Standard Tutorial
7. Click Stored Views
24 of 32
on the 3D Graphics Toolbar.
8. Click New to add the current view to the list of stored views. 9. Double-click the new view and rename it “Fixed Axes”. 10. Click OK. 11. Animate the scenario again. Notice that this time the camera position remains fixed on the DC facility, revolving in sync with the Earth. Using this view we can observe the impact of our scenario on the DC facility for the entire period. 12. Reset the animation. 13. Click View Position and Direction
on the 3D Graphics Toolbar.
STK/VO Standard Tutorial
25 of 32
14. In the View From field, select the LEO satellite. The LEO satellite will also become highlighted in the View To field. Click OK. 15. Manipulate the view in the 3D Graphics window so that the surface of the Earth becomes visible beneath the LEO satellite. 16. Click Stored Views
on the 3D Graphics Toolbar.
STK/VO Standard Tutorial
26 of 32
17. Click New to add the current view to the list of stored views. 18. Double-click the new view and rename it “LEO”, then click OK. 19. Animate the scenario again. Notice that this time the view follows the LEO satellite as it orbits the Earth. 20. Reset the animation. 21. Click Previous Stored View and Next Stored View have created. The Home View is not a part of this cycle.
to cycle between the two views you
22. When you are finished cycling through the stored views, click Home View
.
23. You can also change the view perspective by holding the shift key and double-clicking on an object on the 3D Graphics window. This will have the same effect as setting the view to and from the object by using the View Position and Direction button. 24. Other important 3D Graphics Toolbar features include: Viewpoint Control buttons – Finer , Coarser , and Toggle . The Finer and Coarser Viewpoint Control buttons adjust mouse sensitivity from the default, while the Toggle Viewpoint Control button resets mouse sensitivity to the default. launches a small control panel that allows you to View Pilot – The View Pilot button make small, incremental adjustments to the view. Camera Control –The Camera Control button not covered in this tutorial.
is an advanced animation feature that is
STK/VO Standard Tutorial
27 of 32
Displaying and Modifying a Model All objects in STK are represented in the 3D Graphics window by models. There are default models for standard objects, as well as models designated for specific objects that you might import into a scenario, such as the Hubble Space Telescope, which we will be examining in this exercise. For any object in STK, you can change the model to something other than what is initially assigned to it. In addition to specifying which model is used to represent an object, you can manipulate the appearance of the model itself, as we will do with the Hubble in the second part of this exercise.
Selecting and Viewing a Model in the 3D Graphics window 1. In the Object Browser, select the 3D GraphicsTools scenario. 2. Open the Insert menu on the menu bar, and select Satellite from Database….
3. In the Satellite Database window, enable the Common Name field and enter “hubble” in the associated text box.
STK/VO Standard Tutorial
28 of 32
4. Click Perform Search.
5. In the Insert Satellite window, click on the HUBBLE entry in the list and then click OK. 6. The Hubble Space Telescope is now listed (with the name “HUBBLE”) in the Object Browser and is depicted in the 3D Graphics window. 7. In the Satellite Database window, click Close. 8. Open the Properties Browser for the HUBBLE. 9. Select 3D Graphics - Model.
STK/VO Standard Tutorial
29 of 32
10. In the Model frame, verify that Show is enabled, and that Scale is set to 4.0. 11. In the Detail Thresholds frame, disable Use. 12. To change the model, click the ellipsis button and browse to the model file you would like to use. Since our object is the Hubble Space Telescope and the model file in use for this object is the Hubble model, we will leave this option at its current setting. 13. Click Apply. 14. Select the 3D Graphics window 15. Click View Position and Direction on the 3D Graphics Toolbar. 16. In the View From field, select the HUBBLE. The HUBBLE will also become highlighted in the View To field. Click OK. 17. The Hubble Space Telescope should now appear front and center in the 3D Graphics window.
STK/VO Standard Tutorial
30 of 32
Articulating a Model 1. In the 3D Graphics window, zoom in on the Hubble Space Telescope and manipulate the view so that the solar panels are both plainly visible. 2. In 3D Graphics – Model, click View… in the Articulation frame.
3. When the Model Articulations window appears, move it in the STK workspace so that you can see it and the 3D Graphics window at the same time. 4. Verify that 0 is selected in the LOD frame; this setting provides the most detail for the model’s appearance. 5. In the Articulations frame, select SSARt. 6. In the Transformations frame, select ZRotate. 7. In the slider on the right-hand side, click about halfway between the middle and bottom of the slider so that the value is –36.0. You can also enter this data manually in the text box just to the left of the slider. 8. Looking at the 3D Graphics window, notice the change in the position of the Hubble’s right solar panel.
STK/VO Standard Tutorial
31 of 32
9. Change the value in the Model Articulations window a few more times using the slider. When you finish experimenting reset the slider to 0.0 and click OK. 10. Click OK in the HUBBLE properties window to close it. 11. Click Home View on the 3D Graphics Toolbar to reset your view to the default position.
STK/VO Standard Tutorial
32 of 32
Moving Onward This concludes the Standard Tutorial for STK/VO. There are a number of more advanced features of the VO module that were not covered in this tutorial, such as animation production, web broadcasting, and globe file editing. Please consult STK Help, or see what advanced tutorials are available to learn more about these features.
