LODRoads

Most road editors in the store use fixed spline detail without any LOD. Therefore, one has to choose between performance and having smooth curves even in the sharpest turns. With benefits of adaptive spline detail and procedurally generated levels of details, you can create large networks with fine detail without overloading your GPU with hundreds of thousands of vertices on roads alone.

Tangents of curve nodes are typically calculated as average of direction to next and previous nodes. This results in undesirable curve shapes and makes creation of straight segments unfeasible. You will try to remedy that by adding more nodes, which doesn't work.

LODRoads allow to blend tangents direction between direction to next and previous nodes. If this is still not enough to achieve your desired result, you can edit the tangents manually, having absolute freedom in determining the shape of the road, as illustrated on following picture.

Each spline node can be linked to a Transform object, making both the node's position and tangent relative to the linked Transform. This plain interface enables multiple use-cases: Linking road segments and crossroads to each other, linking roads to custom geometry and possibly even meshes of other road tools. Coupled with position offsetting, merging and joining lanes and multi-level crossroads can be created.

The width of roads and sidewalks can be modulated with custom curves. Roads and sidewalks within one spline can share curves, which allows to easily create roads with choke points or parking places with sidewalks connecting seamlessly to the road.

Creation of railways, walls, pipelines and other line structures is a common feature of road/spline tools, as is spawning of custom prefabs to create light poles or tree alleys. A little addition on top of this is the option to add multiple roads and custom meshes, which enables multilane roads, roads with sidewalks, bridges with roads and sidewalks. Sidewalks with curbs can be generated procedurally, without user-supplied meshes, both on roads and crossroads.

Configurable number and direction of connections, corner sharpness, and UV offset and scale expands the options for road network design. UVs are generated in a way that same materials and textures as on roads could be used. If you need more than the procedural generator can offer, you can use the built-in exporter to save the crossroad as a prefab and enhance its mesh in your favourite 3D modeling software. The exported prefab contains all the link transforms, which lets you easily attach the modified crossroad to the road network.

Sidewalks with separate UV configuration for curb and top can be generated between connections.

Decal painting, which will allow painting crosswalks, road marks and signs, but also cracks and potholes and other textures.

Procedural generation creates a lot of redundant geometry for straight roads or repetitive turns, for example, those that can be found in cities with square road networks. This redundancy can be removed by combining modular and procedural creation of the road system. LODRoads would be extended with controls to assemble, edit and reshape roads as an arbitrary sequence of mesh modules and procedural patches. This is especially important for extruded geometry, like railroads or walls, because those can easily contain hundreds of thousands of unique vertices.

Reverting heightmap changes is unreliable and not user-friendly. The current terrain heightmap painting module is unable to persist heightmap changes, which is currently patched by reverting all LODRoads heightmap changes on scene close and applying them back on scene open. Since detecting scene closed/opened cannot be reliably done in older versions of Unity either, this is again patched by simply reverting heightmap on component disabled, and applying them on component enabled. This causes changes to be reverted on road deleted, on scene recompile, on play and on build, and it still sometimes fails too. Research on how to save terrain heightmaps in Unity seems to be the most promising way to find a solution. The issue of heightmap composition in case of overlapping roads also needs to be adressed. Currently, the heightmap height corresponds to the height of the last applied road, instead of corresponding to the lowest road.

Road networks can be exported as both a mesh and a prefab. The advantage over general-purpose exporters is that all selected roads and crossroad are merged into a single mesh per each LOD, with submeshes for each material used in the selection. Such merger reduces draw calls and number of gameobjects, improving performance and reducing memory footprint.

Road network can be also baked. Similarily to export, the selection is merged by LOD, but the result is placed in scene on the position of the original selection. The selection is either disabled or deleted, depending on choice.