This guide will serve to explain the various components included in the zip file (if you are interested in trying this technique I strongly recommend opening up the .blend included, it's fully set up to render the roads out) and how the roads in this example were created. This method has some really nice advantages over others: It's fast (lots of roads can be blocked out quickly) You can preview the roads and drastically alter them without damaging your terrain as with traditional sculpting You can easily add camber You can give the roads curvature The results will be silky smooth (the main road surface will be roughly as good as a basic mesh road) Setup of the .blend file There are some crucial things that go into making the whole thing work correctly: In render settings you must set it to output 16bit, RGBA, .PNG Render settings: disable anti-aliasing Scene: disable rendering of the sky Scene: disable colour management settings; gamma=1, display device=none, view=default, look=none, color space=linear Your camera and terrain must be set up correctly blender will render out the scene and normalize (lowest point will be black, highest will be white) it so you need to have a "range" object (in my scene I have constructed a ramp from 0m to the 120m - the extents of my terrain's heightmap) or it will create the resulting image in a way that the lowest road is at 0m and the highest 120m (or whatever your terrain is setup as) and your roads will be extremely wrong when placed over your original heightmap ensure your terrain and it's UV map is positioned and rotated correctly for best results make your terrain match exactly pixel to vertex to your source heightmap make sure you select Z as the direction for your displace modifier and UV for texture coordinates as well as setting the strength so that your terrain is properly scaled in terms of it's height The material of your roads and other elements in the render should be shadeless The curves: in settings set Twisting to Z-up. This will make each point independent from each other (mostly). This shows the render node setup of the .blend file. This will be used to render out the heightmap. The spline roads The methods for creating the roads here are similar to what you'd do if you were making mesh roads, the difference is that we will be using them to form the heightmap. To begin with we are using bezier curves as the shaping guide for the roads combined with a mesh that will be arrayed along the curve and deformed so it's shape matches. Take a look at the modifiers used. One of the Modifiers used to create the road A road is created by extruding control points in a bezier curve Components There are three components that go into creating the basic road shape: A bezier curve: this is what we will use to control the road, a few control points and blender does the rest A basic section of road acting as a master road (this will be linked to ("object data" link) and used by many roads across the map, so to change the roads we just edit this object) A linked copy of the master road that will be used for the road itself This shows the elements of the road: orange is the master road, yellow is the bezier curve and black is the resulting mesh road object with modifiers applied Here is a diagram showing the relationship Where you have intersections you can use a separate manual object to manually model over the joins to smooth them over. Exporting the heightmap This part can be as simple or as complex as you want it to be. Essentially you render only the layers with your roads on them and then export that out (disable the layer with the reference terrain on it). Optional: after exporting the heightmap you can delete the road edging from the objects and render again to get a mask of where the actual road surface is (the road object contains the road itself but also some side area that should be dirt or gravel). Combining the roads and the heightmap Open up your original heightmap in an image editor that supports 16bit images (I'm using a development version of Gimp but Photoshop works as well with a bit of tweaking the colour profiles). After that this is the process: import your road export (“blender_roads_out.png”) duplicate this layer twice, call each “blur minor” and “blur major” or something understandable blur each layer by some amount (I used 2px for minor and 15px for major) and then copy and paste each onto itself about 4 times to get some more opacity in the layers This shows how the roads are added to the terrain (the white layer is not used, simply used to show how the layers added affect the heightmap) Note for Photoshop users - Photoshop will always add an alpha channel to PNG files when saving them, even if it's not there. If you try to import one of those, you will end up with a flat terrain ingame. Before saving, flatted the image, then save your PNG. This way the PNG will be 'Greyscale' without Alpha and will be imported correctly. Editing the overlay map You will also want to editor your overlay texture so the changes made show up ingame. For this example I've just done this in a fairly simple way; imported the heightmap (blender_roads_out.png) and use it as a mask for some dirt colour and your heightmap area mask to put down asphalt colour. This image is of the “gimp_overlay.xcf” file that was used to edit the overlay image. Editing the material masks This can be done ingame but it can be faster and more accurate to do it beforehand. Since we're only adding one terrain layer this is pretty easy. We simply open up each of the other layers and add the area of the exported layer (blender_roads_asphalt_area_out.png) before saving it out again. Finally we do the opposite for the layer we're creating (gimp_material_asphalt_out.png). The thing to keep in mind here is that where there is white on one image there can be no white in any other image or you'll get conflicts. Our output layers are as follows: gimp_material_asphalt_out.png gimp_material_grass_out.png gimp_material_rock_out.png This shows the rock material with the roads added as black (asphalt) End result This shows the finished result previewed in Blender This shows the wireframe of the terrain You can see the road has some curvature and camber. Source I have also attached the source files so you can use the .blend for your own projects and look at the other files such as the GIMP xcf files used to combine the roads and heightmap.