Rush Hour Version 1.4.0 Release Notes

Release Notes

About Rush Hour

Rush Hour is an AI-powered toolkit for animating vehicles. Using the real-time physics engine of Unreal Engine, an AI driver will pilot a physically simulated vehicle across a spline-based path. You can select a number of different profiles (Racer, Frantic, Slowpoke, etc) and a profile strength to influence how the AI will behave.

Version 1.4.0 (2023/12/15) notes

This update adds a bunch of new features. Unreal Engine 5.1 is now the minimum supported version.

Release Highlights

Rush Hour Path

Vehicle Animation Path is now called Rush Hour Path

New Waypoint Actions

  • Tap Handbrake - Allows you to tell the AI to tap the handbrake for a period of time, and give it a steering override (-1.0 = turn left, +1.0 = turn right)
  • Stop Destroy - The vehicle will be destroyed after stopping and wait time. Useful for new convoy spawner.

Cornering Force Modifiers

  • Allows you more control over how hard the AI will push corners. Can be set on the whole path as well as per waypoint. These modifiers combine, not override. Be gentle with these settings you can definitely push it too far.
  • Works well with tap handbrake, I find when trying to get a car to do a nice powerslide, modifying the waypoints for that corner to 1.5-2.0 cornering force modifier is a good starting point

Improved Vehicle Physics

  • Resolves issue where vehicles imported through the importer didn’t save a setting causing them to have a high Center Of Mass and be unstable
  • Harder suspension for 4x4 by default to be less bounce-y

Added Center Of Mass Shifting Component for Handbrakes

  • This is useful for making handbrake turns more stable/unstable as you wish.
  • Monitors vehicles for when handbrake is activated, and allows you to specify how the center of mass should shift.
  • Can be added to non-Rush Hour imported vehicles
  • Enabled by default on vehicles imported via Rush Hour

Added Convert To Adopted button on Rush Hour Paths.

  • This spawns the vehicle and sets the path to adopt it instead of spawning a new one. Useful for customizing a car, material, or attaching bodies.

Improved vehicle compatibility

  • There were a few vehicles on the marketplace that Rush Hour didn’t identify as compatible
  • Now doesn’t check vehicles are an AWheeledVehiclePawn , instead only checks that they are an APawn and contain a UChaosWheeledVehicleMovementComponent

New Convoy Spawner Actor Blueprint BP_RH_ConvoySpawner

  • Allows easily setting up basic convoys, to fake traffic and so on
  • Features:
    • Add multiple car types to spawning list
    • Random seed based system so spawning order is repeatable for a given configuration.
      • This means that for a given seed, and a given configuration of the convoy, then the same vehicles should spawn in the same order with the same settings between runs
      • Useful for things like traffic where there won’t be much physics variation due to lower speeds.
    • Spawn in-order or random
    • Set profile strength variation
    • Set timing variation
    • Set number of cars to spawn
    • Easily link to existing path
    • Vary cornering force within random range

Other Changes

  • Unreal 5.0 is no longer supported.
  • Changed names for project DataTables and training map to include a version suffix, like _1_4 . This will prevent DataTables and training maps from previous Rush Hour versions being loaded and causing issues.
  • Fixed glass materials not being reflective in UE 5.2 and UE 5.3
  • Added some example maps for the new features
  • Improved Naming Convention Standards - Renamed a bunch of blueprints, materials and other assets to include RH in the name, moving towards a more consistent naming convention, and improving searchability for Rush Hour classes
  • Added spawn box collision check visualizer for paths which can be shown with rh.showdebug 1
  • Added better spawn collision check handling including logging about which actors are potential colliders
  • Tweaked driver profiles
    • Frantic and racer are slightly less aggressive by default in cornering speed. With the newly added Cornering Force Modifiers you can have more direct control over this now.
  • Added a visualizer box that shows approximate spawn volume that is checked for colliding objects. This can be seen when rh.showdebug 1 is used.
  • Added control bindings for game pads when manually driving (download latest DefaultInput.ini from <HERE>, store page or website)
  • Removed old PhysX references and harnesses from code base
  • Removed some more PhysX references that resolves some build warnings/logspam
  • Fixed issue where cars would freeze, or have strange collisions when off screen
  • Fixed issue where previously changed FBX import scales would affect the imported vehicle assets. Scale is now forced to defaults.
  • Fixed rare issue where cars would never drive forward due to a divide by zero issue.


Template models:

Upgrade Notes

Always remember to backup projects and the current plugin version before updating

Previously recorded sequences with the included vehicles will no longer work due to significant changes to the vehicle classes. You will need to re-record any sequences you wish to use.

Known Issues:

You can potentially spawn multiple vehicles inside each other with Convert To Adopted. If your cars fly off into space when you first start the level, ensure that there isn’t multiple overlapping cars.

Documentation Notes:

If you aren’t seeing all the vehicles spawn with the convoy spawner, it’s probably trying to spawn vehicles too quickly. Check logs for messages like:

LogPhysics: Warning: UWorld::FindTeleportSpot called with an actor that is intersecting geometry. Failed to find new location likely due to movement component's 'UpdatedComponent' not being a collider component.
LogSpawn: Warning: SpawnActor failed because of collision at the spawn location [X=-45410.000 Y=-17880.000 Z=-10729.395] for [BP_RH_Sedan_C]
LogRushHour: Error: Failed to spawn vehicle for path VehicleAnimationPath6, Likely there is not enough space to spawn vehicle. Press Align To Ground.

When you connect a convoy spawner to a path, the paths AutoStart and ForcedSpawning features are disabled automatically. You’ll need to turn these back on if you disconnect the convoy spawner