Basic Usage

This section covers the core workflow for using the Drive Path Editor to create AI vehicle driving paths and behaviors.

Getting Started

Opening the Tool

1. In the World Editor, locate the mode bar at the top

2. Click the Drive Path Editor mode button

3. The tool window will open with a row of buttons at the top

4. The first button is “Add New Drive Path Spline”

Create a New Drive Path Spline

1. Click “Add New Drive Path Spline” in the tool window

2. The mouse cursor sphere on the map will change from red to purple

3. Left-click on the map to place nodes and draw the driving path

4. Continue clicking to add more nodes - the path spline will appear as the user draws

Basic Editing

Moving Nodes

• Mouse method: Click and drag nodes directly on the map

• Gizmo method: Press ALT to toggle the gizmo, then use the translation gizmo handles

Adjusting Path Width

1. Select a node on the drive path spline

2. Look for the rib handles (left and right controls at the node)

3. Drag the rib handles in or out to adjust the path width

4. This affects the AI driving behavior and path following

Adjusting Velocity

1. Select a node on the drive path spline

2. Look for the bar handles (vertical controls at the node)

3. Drag the bar handles up or down to adjust velocity at that point

4. This controls how fast the AI drives through that section

Node Editing

• Select node: Click on any node (it will be highlighted)

• Drag node: Click and drag nodes to move them around the map

• Adding new nodes: Hover over free space on the map to add nodes to either end of the spline (whichever is closer)

• Inserting nodes: Hover over the spline to see a highlight sphere and text hint - click to insert a node

• Delete node: Select a node and press DEL

Spline Operations

• Looping a spline: Drag the start or end node close to the other end - a hint line will appear with text markup. Hold SHIFT and release to create a loop

• Joining splines: Drag the start or end node of one spline onto the start or end node of another spline of the same tool type - a hint line will appear. Hold SHIFT and release to merge them into one spline

• Splitting splines: Select a node on the spline, then click the “Split” button under the spline list to divide the spline into two separate splines at that point

• Simplifying splines: Use the “Simplify” button to reduce the number of nodes to a minimum while preserving the core shape

• Flipping splines: Use the “Flip” button to reverse the order of nodes in the spline, effectively flipping the direction. This will also flip the velocity profile and driving behavior left to right

Recording a Drive Path

Using the Record Feature

1. Prepare the vehicle: Ensure the vehicle is in the desired starting position

2. Click “Record” in the tool window

3. Drive the vehicle along the desired path

4. Click “Stop Recording” when finished

5. The tool will create a spline from the driving path

Recording Notes

1. Drive smoothly: Avoid sudden movements for better path quality

2. Maintain consistent speed: This helps create natural velocity profiles

3. Follow the intended route: Drive exactly where the AI should follow

4. Include key points: Drive through important waypoints and turns

5. End naturally: Stop recording when the desired endpoint is reached

6. The recorded spline can be edited later, like any other path

Linking Vehicles to Paths

Creating Links

1. Select a path spline in the paths list

2. Select a vehicle in the vehicles list

3. Click the link button beside the path or vehicle in their respective lists

4. The vehicle will now be connected to the path spline

5. The link status will be visible underneath both lists

Managing Links

1. Multiple vehicles can be linked to the same path

2. Link status shows which vehicles are connected to which paths

3. Unlink by clicking the same button again (it toggles the link state)

4. Switch vehicles by selecting different vehicles and linking them to the same path

Path Playback and Testing

Testing the Path

1. Select the linked vehicle in the scene

2. Click “Play” or similar button in the tool window

3. The vehicle will follow the recorded path automatically

4. Watch the playback to see how the AI follows the path

5. Stop playback when adjustments are needed

6. Iterate

Playback Controls

1. Play/Stop: Single button which toggles between starting and stopping AI driving

2. Looping: Splines can be set to loop, with configurable number of laps

Velocity Control

Using Bar Handles

1. Select a node on the drive path spline

2. Look for the bar handles (vertical controls above each node)

3. Drag up/down to adjust velocity at that point

4. Higher positions = higher speed (red colors)

5. Lower positions = lower speed (blue colors)

Editing Velocity Profiles

1. Speed variations create natural driving behavior

2. Slow down for turns by lowering velocity at curve nodes

3. Accelerate on straights by raising velocity at straight nodes

4. Smooth transitions between different speed zones

5. Test different profiles to find the right driving feel

Driving Behavior Settings

Available Behavior Controls

1. Delay Time: How long the AI waits before starting to drive

2. Starting Node Index: Which node on the path the AI begins from

3. Route Speed: Alternative speed setting used in some playback modes (overrides velocity profile)

4. Aggression: How aggressively the AI drives

5. Drive in Lane: Whether the AI stays strictly within the path boundaries

6. Avoid Cars: Whether the AI attempts to avoid other vehicles

Using Behavior Controls

1. Start with defaults and adjust gradually

2. Test changes by running playback

3. Balance realism with desired driving style

4. Use route speed when velocity profiles aren’t needed

Path Modes

Free Mode vs NavGraph Mode

1. Free Mode: Unconstrained path drawing (default)

   • Draw paths anywhere on the map
   • Good for custom routes and off-road paths
   • No navigation restrictions
   • Works on any map

2. NavGraph Mode: Waypoint-based path creation

   • Uses existing navigation data
   • Paths follow road networks
   • Good for road-based driving scenarios
   • Map must have a navigation graph

Spline Management

Enabling/Disabling Splines

1. In the tool window, find the spline list

2. Use the enable/disable toggle for each spline (to the right of the name field)

3. Disabled splines: No nodes visible, but content still shows

4. Enabled splines: Full interaction with nodes and editing

Workflow Notes

• Begin with basic paths before adding complexity

• Use playback frequently to verify the path works

• Let the recording feature do the work for natural paths

• Adjust velocity gradually for better results

• Use Free Mode for custom paths, NavGraph for existing road networks

• Test with different vehicles to ensure compatibility

Next Steps

Once comfortable with these basic workflows, the user can explore:

• Advanced velocity profiling techniques
• Different behavior configurations
• Multi-vehicle choreography (e.g., one car moving in front of another, overtaking, etc.)