Road Constructor

Procedural Road Generation and Environment Integration

Road Constructor is a specialized toolset built for Unity 2022 LTS that focuses on the creation of complex road networks through a procedural workflow. By leveraging core Unity packages like unity.splines, unity.burst, and unity.collections, the tool enables developers to generate infrastructure both during the editor-based design phase and dynamically at runtime. The system is designed to handle the logistical challenges of road placement, such as maintaining consistent curvature and managing how roads interact with the surrounding environment.

The package is built around a library of 461 assets, primarily focusing on low-poly geometry to keep performance overhead low. This includes essential roadside props such as street lights, traffic lights, railings, and fences. To support more naturalistic scenes, the tool also provides vegetation assets like birch trees and grass, alongside bridge supports for elevated sections of the road network.

Surface Materials and Visual Standards

The visual identity of the generated roads is managed through a collection of high-resolution textures, provided at 2048×2048 resolution with corresponding diffuse and normal maps. These are categorized into three distinct environment types:

• Rural: Surfaces focusing on dirt and gravel paths.
• Local: Standard asphalt, grass-lined edges, and pavement textures.
• Highway: Specialized layouts for two-lane and three-lane high-speed roads.

To ensure these materials map correctly across complex geometry, the tool includes specific UV options. Developers can choose between cutting or stretching UVs to accommodate different road shapes, ensuring that textures remain coherent regardless of the spline’s length or curvature.

Engineering and Construction Controls

Road Constructor uses a set of dedicated construction settings to maintain technical accuracy across the road network. A grid-based snapping system allows for precise control over distances, curve radiuses, and height increments. For more organic shapes, the tool provides tangent and curvature controls. The generation process also includes a ‘smart reduce’ function, which optimizes the road mesh based on its slope and curvature to reduce unnecessary polygon density while maintaining visual fidelity through LODs (Levels of Detail).

Complexity is managed through specific road components such as construction lanes, roundabouts, and intersection movement nodes. The system supports interconnected waypoints and traffic lanes, which are essential for establishing pathfinding routes. Developers can save configurations as presets to quickly replicate specific road styles across a project.

Terrain and Verification Systems

One of the primary functions of the tool is its ability to modify the Unity terrain to accommodate new infrastructure. The terrain settings allow the system to automatically level the height of the ground beneath the road, remove existing terrain details or trees that would clip through the mesh, and apply texture blending to create a seamless transition between the road edge and the natural environment.

Verification settings are built into the workflow to prevent geometry errors. These include:

• Elevation and Slope Control: Ensures roads do not exceed realistic vertical limits.
• Overlap Control: Detects and prevents clashing geometry at intersections or tight turns.
• Height and Distance Range: Validates the physical dimensions of the splines.

Workflow Compatibility and Traffic Integration

The tool is designed to work within the standard Unity ecosystem, supporting Built-in, HDRP, and URP render pipelines as of version 2022.3.31f1. Beyond simple mesh generation, Road Constructor is built to integrate with external traffic and pedestrian frameworks. It features direct compatibility with the Mobile Traffic System v2.0, Mobile Pedestrian System, and DOTS Traffic City, allowing the procedural paths to serve as the foundation for active AI traffic. This makes it a functional utility for developers building city simulations, racing tracks, or large-scale open environments where manual road placement would be inefficient.

Visual Breakdown