II
Contents
Other Things
Traffic Light Authoring
The ISAT manual has details on authoring a scenario’s traffic lights. Figure 3 shows the settings for a typical type of intersection, with lights along one lane being red for thirty- three seconds then turning green for thirty and yellow for three. Along the other line of traffic, the pattern is reversed. Sometimes you may never want the lights to change, in which case you give them one desired state.
File:Fig3.png
Figure 3 – Traffic Light Authoring Dialog
Triggers Creating Time Triggers
Time Triggers use global time, they are not timers. If you want to create a use a Global Time Trigger as a timer, you will need to modify its activation settings. For example, you may want to play a message, exactly forty-five seconds after the driver passes a certain portion of the road. You would then use a RoadPad Trigger to create a TimeTrigger. Set the TimeTrigger to fire at zero seconds with an activation delay of forty-five seconds.
Persistent Actions
Most actions are completed shortly after they are initiated. So if you are using a trigger, you could have that one trigger do a series or actions. You could create and object, then 5 seconds later, delete it, then 5 seconds later play an audio message, then 10 seconds later terminate the simulation.
Some actions are persistent, that is they are never completed, and could not be part of a series of actions. The persistent actions are those which set some of the ADO’s dials. Specifically, MaintainGap, ForcedVelocity, VisualState, and AudioState. These actions need to be reset, with the reset action, if they will be changed. For example, if you set an ADO’s visual state to display its brake lights, you could not immediately turn on its turn signals. You would have to reset its Visual State and then set it to display brake lights. The ISAT manual gives more specifics on ADO dials and whether they are persistent or not.
Figure 4 shows the settings for a trigger in ISAT-Samples-Avoid.scn. It is described here because it shows how to coordinate several actions at once. The trigger is named: Avoid RPT Move Second Follower. At this point in the scenario, there are two vehicles which have their MaintainGap dial set such that they are following the External Driver at a fixed distance. The first action of the trigger is to create three Time Triggers to do other actions. Then 0.1 seconds later it resets the MaintainGap dial on the vehicle named Second Follower, then 0.1 seconds after that it sets the MaintainGap dial of Second Follower to a different value. It could not do another action after this since MaintainGap is a persistent action and would never be completed.
So the right-most of the three created triggers is a Time Trigger, with a firing time of zero, meaning it will fire as soon as it is created. It resets the MaintainGap dial on the event van, and then gives that dial another setting, making the Event Van move closer to the External Driver.
The middle trigger is a Time Trigger with a firing time of zero, but an Activation Delay of five seconds. It will therefore fire five seconds after it is created. It affects the Second Follower by making it change lanes to the right. This action could not be done as part of the trigger shown below since its final action, setting the MaintainGap dial, will never be complete.
The left most, of the three triggers, is also a Time Trigger, with an Activation Delay of 10 seconds. It fires and resets the Second Follower’s MaintainGap, and then sets it ForcedVelocity dial to 83 mph so that it speeds out ahead of the Driver.
File:Fig4.png
Figure 4 – Sequential Action Example
Sample Scenarios
The data directory contains a few sample scenarios that illustrate some of the points in this document, as well as showing how to author simple events.
ISAT-Samples-Right-Incursion.scn
In this scenario there is an incursion from the right. Figure 5 shows a view of the main action. The selected trigger creates the incurring vehicle (the white car), when the driver is 1.85 seconds away from the driveway. The Roadpad Trigger next to is set to make the oncoming car slow down, to simulate another driver attempting to avoid the accident. The Roadpad Trigger also creates the TimeTrigger above which sets the ForcedLaneOffset of that oncoming vehicle, causing it to also pull off the road in an attempt to avoid the accident.
To get the oncoming car to always be in the correct location, it (and another vehicle behing it) are created 2,500 feet from the event, when the driver is 2,500 feet from the event. As soon as it is created, it hits a Roadpad Trigger which sets its ForcedVelocity Dial to match the velocity of the driver, and also sets the ForcedVelocity Dial of the car behind it. This setting is shown in Figure 6. Creating the car this way ensures that no matter the speed of the driver, it will always be at the appropriate distance from the event.
ISAT-Samples-Left-Incursion.scn
This scenario is similar to the right incursion, except the incursion occurs from the left. A car pulling out into the road, causes the car behind it to pull into the driver’s lane. The oncoming car is set to be at the correct distance from the event, in the same manner as the right incursion scenario. Figure 7 shows the event location with the TimeToArrival Trigger which creates the pulling out car when the driver is six seconds away. The other TimeToArrival Trigger causes the oncoming car to pull into the driver’s lane when the driver is 3 seconds from the event.
This scenario also uses traffic, parked vehicles, and signs, as an external reference from the right scenario.
ISAT-Samples-Avoid.scn
In this scenario, the driver is instructed to stay in the right lane. When the cars that are following the driver, get to the four lane portion of the road they start to pass the driver.
Eventually a construction van passes the driver and maintains its position in front of the driver. Within that van is a desk named AvoidDesk. Its settings are shown in Figure 8. Even though the desk is on the ground, somewhere in the scenario, when the scenario starts it is coupled to the van, sitting at 1.46 feet above the center of the van, as shown by its Relative Offset settings.
Figure 10 shows the three triggers that cause the event. The first trigger starts the van doors opening, and is shown in Figure 11. Opening of the doors is a visual state. Since the van has no other visual state set, the dial does not need to be reset, before it is set. The next trigger causes the desk to start sliding, relative to the van, and its settings are shown in Figure 12. It does this by changing its state from Coupled (state 2) to Relative (state 3). When it is moving in the Relative state, it is following its own path, but moving relative to the van in which is initially located. The actual path of the Desk is shown in Figure 9. The last trigger, shown in Figure 13, drops the desk, by changing its state to free (state 1). When its state changes, it receives the Initial Velocity shown in Figure 8, where the first three components are the x, y, and z components. While the last three are the roll, pitch, and yaw components.
File:Fig11.png
Figure 11 - Open Van Doors
File:Fig12.png
Figure 12 - Slide Desk
ISAT-Samples-TrafficLight.scn
This scenario has two traffic light intersections, and the Traffic Light Manager has been used to set the traffic light pattern.
ISAT Scripting
ISAT uses a custom language (ISC) to automate placement and manipulation of scenario objects. Combined with simple direction commands and the capability to navigate a road network, ISC scripts can ask the scenario author for input and prompt for selecting objects.
Scripts are an efficient way to automate repetitive and/or complex tasks.
ISAT installs with some ISC script files. If your version of ISAT contains a data\isc folder, then your version of ISAT is capable of running scripts. You can create additional scripts as needed. All scripts located in the data\isc folder will load in ISAT when ISAT is launched.
New scripts created during an existing ISAT session will not appear until ISAT is re-launched.
Scripts that have been edited will not update until ISAT is re-launched.
You can use these scripts for reference in creating your own custom scripts.
Unless otherwise indicated, scripts are case-sensitive.
NOTE: Please do not edit the existing scripts!
Make a copy of any existing script before you make changes. In the event your modified script does not work, you can look at the original file for reference.
Icon Files
Script icon files are 8-bit windows icon files (file.ico). GIMP is capable of exporting valid ico files. To create an ico file, scale it to 32x32 pixels. Export the file as .ico to the isat\data\isc folder.
In order for a script to use an icon file, both files must exist in the isat\data\isc folder.
Examples
This section contains example scripts.
Rotate sign
# prompt author for a sign to rotate
.Name SetSignRotation
.Icon SignRot.ico
Static sign
Select(sign,"Please Select a Sign")
sign.SetAngle(Anchor)
.End
Reference
File:ISC_Image2011_ISC.pdfImage ISC Paper
