Splines

What Are Splines

Splines are 3D paths that follow roads, tracks, and other linear features from your OpenStreetMap data. They're essential for AI vehicle navigation and can also be used for decorative purposes like fencing or pipeline routes.

File Output: Maps4FS creates a splines.i3d file containing all the extracted spline paths from your map area.

Adding Splines to Your Map

Import Process

1. Open Giants Editor: Load your map project

2. Import Splines: Go to File → Import and select splines.i3d

3. Verify Import: Splines should appear as 3D paths following your roads

Positioning and Alignment

Initial Position: If your map has roads covering the full area, splines should be centered correctly. If roads only exist on part of your map, you'll need to adjust their position.

Create a Group:

1. Select all imported splines

2. Right-click and choose Create Group

3. This lets you move all splines together

Height Adjustment

Z-Axis Alignment (called Y-axis in Giants Editor):

• Transform Y: Move splines up or down to match terrain height

• Scale Y: Adjust vertical scale if splines appear too tall or short

• Follow Terrain: Ensure splines sit properly on roads and don't float or sink underground

Using Splines for AI Traffic

Setup for Auto-Drive

1. Select All Splines: Choose your spline group

2. Create TransformGroup: Group them if not already grouped

3. Add AI Attribute:

   • Select the TransformGroup

   • Open Attributes panel → User Attributes tab

   • Add new attribute:

     • Type: Script callback

     • Name: onCreate

     • Value: AISystem.onCreateAIRoadSpline

AI Spline Configuration

Result: AI vehicles will use these splines for autonomous driving on roads.

Common Issues and Solutions

Misaligned Splines

Problem: Splines don't follow roads correctly Solution: Check your OpenStreetMap data quality and regenerate if needed

Height Problems

Problem: Splines float above or sink below terrain Solution: Use Transform Y tool to adjust height, or Scale Y to fix vertical proportions

Missing Splines

Problem: Some roads don't have splines Solution: Improve OSM road data coverage in your area before regeneration

Spline Quality Tips

OSM Data Quality: Better road data in OpenStreetMap = better splines Road Types: Major roads (highways, primary) typically generate more reliable splines than minor paths Map Edges: Roads that cut off at map boundaries may need manual adjustment