Making roads ... on a terrain

Not sure how to approach this one but I’d like to overlay a winding road on a terrain. I could try simply adding additional textures to the terrain but the mesh polygon count is low and I’d like the road to look fairly detailed.

I’ve looked around and whilst many games achieve the look that I want there’s nothing around that explains how it is achieved ?



There are two main ways (+ lot’s of derivatives)

the first one is exactly as you describe as just textures overlayed on the terrain, if the quality is good enough this works pretty well, this will probably the best solution for you.

the second one involves using a separate object for the road surface, it means you can have a lot higher quality but does have some problems joining up the seams, most racing games use this method

Thanks … I’ve crafted most of the terrain by hand, actually from heightmaps and I guess that I need to start considering tools to either create my mesh including a road texture or to create a secondary road object … any suggestions ?


The road can be the same object like the terrain. The road height should be filtered with a large blur kernel. For example in gimp: Load the heightmap, mark the road and use gaussian blur to planate it.

Also I think it kinda depends on what you mean by “detailed”. It might mean you don’t want a bad case of the jaggies at steep shoulders and such (where the shoulder suddenly gives way to a steep embankment), which might require further tessellation or some heavy smoothing, as oc2k1 suggested, to avoid.

Thanks for the feedback, I went with a separate road overlay mesh just wasn’t sure if there was something more obvious. It works very well but a real pain to produce … FreeWorld3D helped a lot but it was one hell of a fiddle as its export features are a bit restricted … the road being exported as a text file ! (That aside it works and has many good features.)