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105. Validating and creating Foretify-compatible scenarios

During the scenario extraction, the system examines the trajectory of each actor to ensure that a valid, drivable path exists between the trajectory points. This analysis checks if the actor’s recorded maneuvers are feasible on the actual map, for example, whether the vehicle stays on mapped roads and avoids impossible transitions like jumps over medians or off-road segments, or illegal maneuvers, such as the actor driving against the direction of the road which are not allowed in Foretify.

The validation behavior depends on the extraction mode you select: Exact Mode or Behavioral Mode.

105.1 Exact Mode

In Exact Mode, actors are forced to follow the exact path from the recorded data.

105.1.1 Permissions after connectivity checks

Extraction might be permitted despite potential connectivity issues. This is because, after the scenario generation, if such issues are detected, the system attempts to create temporary virtual roads that allow actors to follow the recorded path precisely, even if it deviates from the standard road network. Consequently, the scenario will run successfully in Foretify.

Use this mode when you need to replicate the exact recorded trajectory, regardless of minor deviations from the map's road network.

105.2 Behavioral Mode

In Behavioral Mode, actors follow the general trajectory using the existing road network. They are allowed to deviate from the predefined path because they are governed by the rules of the road.

105.2.1 Permissions after connectivity checks

Extraction might be blocked if potential connectivity issues are detected. This is because behavioral actors cannot drive on virtual roads and must adhere to the legal road network. Since an impossible maneuver (like jumping across a median) would cause a failure in Foretify, the extraction of an actor through disconnected roads is prevented.

105.2.2 Error messages after connectivity failures

If a scenario extraction in Behavioral Mode fails the validation check, the process is blocked, and a corresponding error message is provided.

Error message format: "The following actors drive through paths with connectivity issues and cannot be used in [Mode] Smart Replay scenarios: [Actor Names]. Issues detected: [List of Issues]. Consider using exact replication or removing these actors."

Example error message: "The following actors have non-foretifyable connectivity issues and cannot be used in behavioral Smart Replay scenarios: Vehicle_101, Truck_08. Issues detected: Path segment is off-road, Gap detected between maneuvers. Consider using exact replication or removing these actors."

Understanding the error message:

  • [Mode]: Confirms the mode you selected where the error occurred.
  • [Actor Names]: Provides the actor names in the selection that have invalid paths (e.g., Vehicle_101, Truck_08).
  • [List of Issues]: Describes the reason for invalid paths, which facilitates a rapid diagnosis of the root cause (e.g., the vehicle's path goes off-road or has an impossible jump between two points).
  • Suggestions: The message concludes by recommending the two primary solutions: using "exact replication" (Exact Mode) or removing the problematic actors.

Fixing connectivity errors:

As the error message suggests, you have two primary options:

  • Switch to Exact Mode (Exact Replication): Re-extract the same scenario by selecting Exact Mode.
  • Adjust Your Data: If you must use the Behavioral Mode, you need to adjust your data selection. Use the [Actor Names] and [List of Issues] from the error message to locate the problem. Review the trajectory of the failing actors and either shorten the time range, adjust the start/end points, or completely remove them from your selection to ensure the path is fully on a drivable surface.

Note that there might still be cases where replay is not be possible and detected only during run time