Terrain objects

TerraExplorer provides a set of objects that affect the terrain. You can modify the terrain, create holes in the terrain and play a video file onto the terrain.

Objects Tab

Modifying the terrain

Using the Modify Terrain tool, you can modify the elevation values in an area of the terrain by drawing a polygon in the 3D Window and then setting the Modify Terrain object’s properties in its property sheet. The surface of the terrain is raised or lowered according to the elevation values of the polygon's points. Different elevation behaviors allow replacing, cropping above or cropping below the original values of the terrain. The interior of the polygon can be flat or irregular in shape. You can modify the elevation values of a mesh layer by drawing a modify terrain object and applying it to the mesh layer.

To modify the terrain:

1. On the Objects tab, in the Terrain Objects group, click Modify Terrain. The Modify Terrain property sheet is displayed.

2. If you want to position the modify terrain object based on where the mouse is pointing in the 3D Window, on the top bar of the label’s property sheet, click Set Position Based on Mouse . See "Moving an Object Based on Where the Mouse is Pointing in the 3D Window" in the "Working with Objects" chapter for more information.

3. If you want to position the modify terrain object in the Z plane, on the top bar of the object’s property sheet, click Z Plane . See "Moving an Object in the Z Plane" in the "Working with Objects" chapter for more information.

4. With the cursor in the 3D Window, click to add the first point of the polygon.

5. Click again to add additional points of the polygon until you have marked the entire shape. You must place at least three points to define the polygon.

Note: When creating a Modify Terrain object, the lines of the polygon should not overlap each other.

Note: It is recommended to keep the number of polygon points to the minimum required to define the shape. Adding unnecessary points may adversely affect performance.

6. Right-click to finish the object.

7. Continue to edit the object’s parameters and shape or close the property sheet to finish the operation.

Modify terrain property sheet parameters

Object Parameter	Activity
Modify Terrain
Flat	If Yes is selected, sets all points of the modified terrain at the same altitude, creating a horizontal flat surface.
Elevation Behavior	Defines how the modified terrain elevation values affect the terrain's elevation: § Replace: replaces the area defined by the modified terrain with the selected altitude value. § Crop Below: replaces all elevation values that are lower than the selected elevation value with the selected altitude value. § Crop Above: replaces all elevation values that are higher than the selected elevation value with the selected altitude value. § Offset: offsets the area defined by the modified terrain with the selected altitude value.
Feather	Determines the distance along which the gradual fading of the edges of the modified terrain is applied. Applying a feather creates continuous diagonal surfaces. These surfaces start from the terrain database elevation value on the polygon to the modified terrain elevation value at its respective point on the feather polyline. Gradual fading of the edges is applied within the distance defined by the radius parameter. Type the required radius.
Apply To	Determines what surface the terrain modification object is applied to. If there is a 3DML in the area of the modify terrain object, click the arrow, and then select either of the following: § Terrain – Changes the elevation values only of the terrain, without modification to the 3DML. § [name of the 3DML] – Changes the elevation values of the specified 3DML. Note: A modify terrain object can also be applied to a 3DML from the 3D Layer tab. See "Modifying a 3D Mesh Layer" in the "3D Layers" chapter for information.
General
Tree Name	Type the description or name of the modified terrain. This text appears in the Project Tree as the name of the object.
Message	The message associated with the object. The number displayed is the number of the message. To create a new message, or update an existing message, open the Create Message dialog by clicking in this field and selecting Edit. See "Using the Create Message Dialog" in the "Working with Objects" chapter for more information.
Tooltip	Type a tooltip text to appear when the mouse cursor is placed over the modified terrain in the 3D Window.
Position
Altitude Method	Sets the altitude method to be used by the modified terrain. Always set to On Terrain.
Altitude	Enter the altitude, as defined in Altitude Method, for the modified terrain pivot point, the center of its base.
X	Enter the X-coordinate for the modified terrain’s pivot point. The pivot is located at the center of the modified terrain. Change this value to move the entire object.
Y	Enter the Y-coordinate for the modified terrain’s pivot point. The pivot is located at the center of the modified terrain. Change this value to move the entire object.
MGRS	The coordinates of the modified terrain’s pivot point in Military Grid Reference System (MGRS) coordinates. This field is only available if Show MGRS Coordinates was selected in the Options dialog. See "View" in the "Using TerraExplorer Options" chapter for more information.
Points Position The parameters in this group are enabled only when Edit Nodes is selected on the property sheet top bar.
Selected Point	Select the point to edit. The selected point is highlighted on the 3D Window. When you edit this point, the corresponding point on the modified terrain changes accordingly.
Point X	Enter the X-coordinate for the selected point.
Point Y	Enter the Y-coordinate for the selected point.
Point MGRS	The coordinates of the selected point in Military Grid Reference System (MGRS) coordinates. This field is only available if Show MGRS Coordinates was selected in the Options dialog. See "View" in the "Using TerraExplorer Options" chapter for more information.
Point Altitude	Enter the altitude, as defined in Altitude Method, for the selected point.
Timespan
Start Time	Click Edit and enter the date and time the modified terrain should first become visible.
End Time	Click Edit and enter the date and time the modified terrain should stop being visible.

Cutting a hole on terrain

Cutting a hole on the terrain removes the terrain texture while maintaining the original contours of the terrain. The objects or feature layers created on the terrain in the area of the hole are drawn on the original contours of the terrain.

To cut a hole on the terrain:

1. On the Objects tab, in the Terrain Objects group, click Hole on Terrain. The Hole on Terrain property sheet is displayed.

2. With the cursor in the 3D Window, click to add the first point of the hole.

3. Click again to add additional points of the hole until you have marked the entire shape.

4. Right-click to finish the hole.

Note: It is recommended to keep the number of hole points to the minimum required to define the shape. Adding unnecessary points may adversely affect performance.

5. Continue to edit the hole or close the property sheet to finish the operation.

Hole on terrain property sheet parameters

Object Parameter	Activity
Appearance
Line Color	Select the outline color for the Hole on Terrain. Click the Edit button to open the Color dialog, or type the color code in hexadecimal BBGGRR format (B = Blue channel 00-ff, G = Green channel 00-ff, R = Red channel 00-ff).
Line Opacity	Enter the opacity for the Hole on Terrain outline. The opacity is defined as a percentage, where 100% is opaque and 0% is transparent.
Line Style
Line Width	Enter the Hole on Terrain line width, in the selected Line Width Units.
Line Width Units	Select Pixels or Meters/Feet. If Meters/Feet is selected, the unit displayed, meters or feet, depends on the setting in the View tab of the Options dialog. See "View" in the "Using TerraExplorer Options" chapter.
Line Back Color	Sets the Hole on Terrain line back color. Click the Edit button to open the Color dialog, or type the color code in hexadecimal BBGGRR format (B = Blue channel 00-ff, G = Green channel 00-ff, R = Red channel 00-ff).
Line Back Opacity	Enter the Hole on Terrain line back opacity. The opacity is defined as a percentage, where 100% is opaque and 0% is transparent.
Line Spline	Determines if the line around the Hole on Terrain is drawn as a curve based on its nodes.
General
Tree Name	Type the description or name of the Hole on Terrain. This text appears in the Project Tree as the name of the object.
Message	The message associated with the object. The number displayed is the number of the message. To create a new message, or update an existing message, open the Create Message dialog by clicking in this field and selecting Edit. See "Using the Create Message Dialog" in the "Working with Objects" chapter for more information.
Tooltip	Type a tooltip text to appear when the mouse cursor is placed over the Hole on Terrain in the 3D Window.
Position
Altitude Method	The altitude method used by the Hole on Terrain. Always set to On Terrain.
Altitude	The altitude of the Hole on Terrain is always set to zero, meaning on the surface of the terrain.
X	Enter the X-coordinate for the Hole on Terrain pivot point, the center of its base.
Y	Enter the Y-coordinate for the Hole on Terrain pivot point, the center of its base.
MGRS	The coordinates of the Hole on Terrain pivot point in Military Grid Reference System (MGRS) coordinates. This field is only available if Show MGRS Coordinates was selected in the Options dialog. See "View" in the "Using TerraExplorer Options" chapter for more information.
Points Position The parameters in this group are enabled only when Edit Nodes is selected on the property sheet top bar.
Selected Point	Select the point to edit. The selected point is highlighted on the 3D Window. When you edit this point, the corresponding point on the hole changes accordingly.
Point X	Enter the X-coordinate for the selected point.
Point Y	Enter the Y-coordinate for the selected point.
Point MGRS	The coordinates of the selected point in Military Grid Reference System (MGRS) coordinates. This field is only available if Show MGRS Coordinates was selected in the Options dialog. See "View" in the "Using TerraExplorer Options" chapter for more information.
Point Altitude	The altitude of all the points is always set to zero, meaning on the surface of the terrain.
Visibility
Max. Visibility Distance	Sets the distance from the camera at which the Hole on Terrain disappears.
Min. Visibility Distance	Sets the minimal distance from the camera below which the Hole on Terrain disappears.
Viewing Distance	Determines the viewing distance of the camera from the Hole on Terrain. This distance is used as a stop mark for any "Fly-to" or "View Object" operation. It is also used when selecting to edit the object from the Project Tree. When this value is set to the default of -1, TerraExplorer calculates and sets the ideal viewing distance for the Hole on Terrain based on its size.
Activation Action	Select the action to perform when selecting the Hole on Terrain from the Project Tree.
Timespan
Start Time	Click Edit and enter the date and time the hole on terrain should first become visible.
End Time	Click Edit and enter the date and time the hole on terrain should stop being visible.

Video on terrain and video billboard

The Video on Terrain/Video Billboard commands play a video file either on a selected area of the terrain (Video on Terrain), or on a floating billboard (Video Billboard). Both these commands open the same property sheet and can be converted one to the other by changing the default properties. The primary difference between the two is the distance from the projector at which the video should be displayed (Maximum Projection Distance property set in the property sheet). When this distance is set to zero, the video is projected on the terrain.

The positioning of the projector and the projected video can also be determined using telemetry data that holds positioning information for the camera based on time stamps. The telemetry data can either be embedded in the video file or contained in a separate telemetry file.

Supported video file formats are determined by the codecs that are installed and registered on your computer. Most files that Windows Media Player can play (e.g., *.avi, *.mpg, .mov, etc.), including streaming Microsoft Media Server (MMS) content, can be draped on the terrain.

TerraExplorer supports the KLV (Key Length Value) format for videos with telemetry information (MISB 0601 standard). TerraExplorer can parse this data and place the video correctly on the terrain

Creating a video on terrain/video billboard

To create a video on terrain:

1. On the Objects tab, in the Video group, click Video on Terrain/Video Billboard. The Video property sheet is displayed.

2. If you want to use telemetry data, which is either embedded in the video file or contained in a separate telemetry file, do the following:

a. In the Use Telemetry File, select Yes.

b. In the Video File field, type or browse to a video file, whose format is supported, or type the URL (e.g., mms://mms.skylinesoft.com/) if you want to open streaming MMS content. For video files with telemetry information, TerraExplorer supports the KLV (Key Length Value) format (MISB 0601 standard).

c. If your telemetry data is contained in a separate telemetry file, in the Telemetry File Name field in the property sheet, enter the Telemetry File Name.

3. If you want to set the object’s location by defining a point in the 3D World, do the following:

a. In the Video File field, type or browse to a video file, whose format is supported, or type the URL (e.g., mms://mms.skylinesoft.com/) if you want to open streaming MMS content.

b. In the Use Telemetry File, select No. Then click the mouse in the 3D Window to define the location of the projector.

4. After an object has been placed on the terrain, you can change its properties using the property sheet.

Playing, pausing and stopping the video

To play, pause or stop the video, do either of the following:

§ In the Project Tree, right-click a Video On Terrain/Video Billboard object and select the required option from the shortcut menu.

§ In the 3D Window, right-click a Video On Terrain/Video Billboard object and select the required option from the shortcut menu.

Using a telemetry file

A telemetry file holds positioning information for the camera based on time stamps. This information is used to automatically determine the position of the video projector in the 3D Window. This allows the projected Video On Terrain to be draped over the same area that is captured in the video.

The file is a comma-delimited text file, with each line representing the location parameters for a certain time stamp. Each value should be a decimal number in double-precision floating-point range.

The following values should appear for each point:

Value	Description
Time	The time elapsed, in seconds, from the beginning of the recording. The first point should be set to zero. Following points can use any increasing value, including fractions (e.g., 0.3) to represent parts of a second.
X	The X-coordinate (Longitude) of the camera.
Y	The Y-coordinate (Latitude) of the camera.
Height	The height of the camera above the terrain database vertical datum base ellipsoid.
Roll	The Roll of the camera, in degrees.
Pitch	The Pitch of the camera, in degrees.
Yaw	The Yaw of the camera, in degrees. This is the direction in which the camera points.
Field of View	The horizontal field of view covered by the camera, in degrees.

Video on terrain/video billboard property sheet parameters

Object Parameter	Activity
Appearance
Activation Action	Select the action to perform when selecting the imagery layer from the Project Tree.
Video
Video File	Type the full path of the file, or use the Edit button, for a supported media file. You can also type a URL for an MMS server. Supported video file formats are determined by the codecs that are installed and registered on your computer. Most files that Windows Media Player can play (e.g., .avi, .mpg, etc.), including streaming Microsoft Media Server (MMS) content, can be draped on the terrain. TerraExplorer can also use RTSP, or any custom protocol using "video:myprotocol://" for any custom protocol that is defined on your system: e.g., "video:custom1://".
Use Telemetry	Determines how the position is defined. Choose No to set the object’s route by placing the projector in the 3D World or Yes to link the object to an external set of files containing telemetry information.
Telemetry File Name	Type or browse a path to a .csv telemetry file.
Field Of View	Enter the horizontal field of view, in degrees, covered by the camera.
Calculate Hidden Surface	Calculate which surfaces are visible to the projector, and project video only onto these surfaces. Note: Selecting this option will slightly increase TerraExplorer's resource usage, but will result in a more realistic result.
Opacity	Enter the opacity for the Video object data. The opacity is defined as a percentage, where 100% is opaque and 0% is transparent.
Max. Projection Distance	Maximum distance from the projector at which the video should be displayed. Set to zero to project on the terrain.
Disable Soundtrack	Determines if the audio information in the video file is played. Choose No to play the soundtrack, or Yes to disable it.
Volume Classification	Enter the audio volume level. The level is defined as percentage, where 100% is the maximum volume and 0% is the minimum.
Play Video on Startup	Determines if the video starts playing when a FLY project opens. Choose Yes to play the movie automatically when a FLY file opens or No to instruct the video to wait for a play command.
Projector
TerraExplorer can display objects to mark the location of the video projector. A pyramid is used to show the position, orientation and field of view of the projector. Four lines originating from the projector’s location to the ground mark the projector rays. This group defines the appearance of the projector objects in the 3D Window.
Show Projector	Determines if the projector pyramid object is displayed in the 3D Window.
Projector Color	Select the color for the projector pyramid object. Click the Edit button to open the Color dialog, or type the color code in hexadecimal BBGGRR format.
Projector Size	Enter the height of the projector pyramid.
Show Projector Rays	Determines if the projector rays object is displayed in the 3D Window.
Projector Rays Color	Select the color for the projector rays object. Click the Edit button to open the Color dialog, or type the color code in hexadecimal BBGGRR format.
Position
Altitude Method	Sets the altitude method to be used by the Video object: § Select Relative to Terrain to place the projector’s position at a specified altitude above the ground. § Select Absolute to place the projector’s position at a specified altitude above the terrain database vertical datum base ellipsoid.
Altitude	Enter the altitude, as defined in Altitude Method, of the video projector.
X	Enter the X-coordinate for the video projector.
Y	Enter the Y-coordinate for the video projector.
MGRS	The coordinates of the video projector in Military Grid Reference System (MGRS) coordinates. This field is only available if Show MGRS Coordinates was selected in the Options dialog. See "View" in the "Using TerraExplorer Options" chapter for more information.
Yaw	Determines the direction angle of the video projector along the vertical axis relative to north.
Pitch	Determines the tilt angle of the video projector along its lateral axis relative to the horizon.
Roll	Determines the roll angle of the video projector along its longitudinal (front-to-back) axis.
General
Tree Name	Type the description or name of the Video object. This text appears in the Project Tree as the name of the object.
Message	The message associated with the object. The number displayed is the number of the message. To create a new message, or update an existing message, open the Create Message dialog by clicking in this field and selecting Edit. See "Using the Create Message Dialog" in the "Working with Objects" chapter for more information.
Tooltip	Type a tooltip text to appear when the mouse cursor is placed over the video object in the 3D Window.
Visibility
Max. Visibility Distance	Sets the distance from the camera at which the video object disappears.
Min. Visibility Distance	Sets the minimal distance from the camera below which the video object disappears.
Viewing Distance	Determines the viewing distance of the camera from the video object. This distance is used as a stop mark for any "Fly-to" or "View Object" operation. It is also used when selecting to edit the object from the Project Tree. When this value is set to the default of -1, TerraExplorer calculates and sets the ideal viewing distance for the video object based on its size.
Timespan
Start Time	Click Edit and enter the date and time the video should first become visible.
End Time	Click Edit and enter the date and time the video should stop being visible.