DDO Authoring
ISAT User's Guide Table of Contents
Contents
DDO Authoring
Creating a DDO
To create a new DDO, select the menu option Insert->Local Scenario Element->Deterministic
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Objects->Path Follower or click on the appropriate toolbar icon:
The cursor will turn into the insertion cursor:
Now left click on the map to place the DDO. Once placed the properties dialog will appear. There are four separate tabs in the dialog: SOL Model, Deterministic Object, Visual/Audio States, and Path Speed Chart. The SOL Model tab allows selection of the model to be associated with the DDO. See Section 3.17.5 for more details on the selection of the SOL model. The functionality of the remaining tabs is described below. After setting the parameters click on the OK button, and the DDO will appear on the map. At any time, double-click on the DDO or right-click and select Settings to cause the DDO properties dialog to appear again.
Defining DDO-specific Parameters
The second tab in the dialog box titled “Deterministic Object” contains DDO-specific parameters. Since DDOs have a very simple behavioral model, there is only one parameter in addition to the standard ones described in Section 3.17, namely the Quit at End parameter. This flag specifies what the DDO should do once it reaches the end of its path. If the flag is set, then the DDO will delete itself once it reaches the end of its path; otherwise, it will remain stationary at the last node of its trajectory.
Specifying Visual and Audio States
The third tab, titled Visual/Audio States, allows the specification of non-standard initial conditions for the various visual and audio indicators possible for the specified SOL model. For example, most vehicle models can have their headlights or turn signals operating or can generate sounds such as sounding the horn or, in the case of emergency vehicles, sounding the siren. Since DDOs have no built-in behaviors that will control these effects, the ISAT allows the user to specify the initial visual or audio state of a DDO. Figure 4-45 illustrates the contents of the dialog box tab.
In addition to some typical visual effects that can be associated with various objects, several special effects generally apply only to a small subset of the SOL categories. For example, the Stop Sign that applies to school buses and represents the unfolding Stop sign in the front of the bus. Finally, the Driver Select pull-down menu allows selection of the driver inside the vehicle.
If the selected SOL model does not support any of the choices available in the dialog box, then they would be grayed out.
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Figure 4-45 Setting the visual and audio states of DDOs.
Visualizng the DDO Velocity Profile
The last tab, titled Path Speed Chart is a read-only dialog box that presents a visual representation of the velocity profile associated with the DDO. The dialog box is useful when trying to verify the velocity that will be followed by the DDO without having to go through each control point one by one. Figure 4-46 illustrates an example of this dialog box.
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Figure 4-46 Speed chart.
Specifying the DDO path
Once all necessary parameters have been defined, click on the OK button on the tabbed Deterministic Object dialog box. The dialog box will disappear, and the selected SOL object will appear on the map. At this point, it will have a random orientation and no path will be associated with it. To add a path, right-click on top of the SOL model and select Add Path Nodes on the pop- up menu. The cursor will change into crosshairs:
This indicates that the tool is ready to receive mouse clicks specifying the trajectory. Click the left mouse button to specify the location of the next trajectory control point. Immediately after clicking, the dialog box shown in Figure 4-47 appears.
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Figure 4-47 Specifying the speed on a control node.
Type the speed that the DDO should be traveling when crossing the particular control point and hit Enter or click on OK. The system is then ready to receive another control point. After each click of the left mouse button, the dialog box shown in Figure 4-47 will appear. If the speed on all nodes is to be the same, then check the box titled "Use same speed for all following nodes," and the tool will automatically use that speed for the remaining control points without popping up the dialog box after each mouse click.
To end specifying trajectory control points, click the right mouse button. At that point, the DDO is fully specified.
Editing the DDO path
Once the DDO parameters and its trajectory have been specified, it is easy to modify either the velocity associated with each control point or the number and placement of the control points or the orientation of DDO at each control point.
Adding control points at the end of the current path
To add additional points at the end of the trajectory, right-click on the DDO and select the option Add Path Nodes. Then follow the process described in Section 4.2.2 to add control points.
Adding a control point after an existing node
To add a new control point located after an existing control point, place the cursor over the control point after which the new one is to be added, and click the right mouse button. Select the option Insert Node from the pop-up menu. A new node appears halfway between the node that was right- clicked and the next one.
Editing the node velocities
To change the velocity associated with any of the nodes of a DDO, place the cursor over the control point whose velocity is to be modified and click the right mouse button. Select the option Edit Speed. The dialog box shown in Figure 4-48 appears.
Type the new velocity to be associated with this node and hit Enter. This will cause the new velocity to be associated with the selected node, and the dialog box will go away. Instead of hitting Enter, use the buttons titled Previous Node and Next Node to change the selected node and modify its speed without continuously popping the dialog box up and down. To help visualize which control point's speed is modified; click the Center View on the Current Node button to cause the whole scene to be redrawn with the affected node in the center. Click Accept to activate all changes, or Cancel to abandon all changes made to all nodes.
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Figure 4-48 Editing the speed of control points.
Editing DDO's orientation at each node
The default orientation of DDO is along the direction of the path. To change the orientation of a DDO at any of the nodes, place the cursor over the node and click the right mouse button. Select the option Rotate to change orientation. By selecting Rotate, the arrow associated with the node can be rotated in a circular fashion around the node and can be set to a specific orientation by clicking left mouse button.
Deleting a node
To delete one of the nodes in a DDO trajectory right-click on the node, and then select Delete Node.
DO NOT: Selecting a particular node and hitting delete button on the keyboard would delete the DDO, instead of a particular node.
