My map, which is 8184x8184m in size has geometry spaced at 2 metre resolution (squares of 2x2m, although there are triangles dividing it). The problem with this is that it is a bit too low for shaping everything, especially sloping roads which I have found to be very difficult to make smooth enough to drive comfortably at highway speed. The best case scenario is that I can somehow set the terrain to be higher resolution, say 1 metre resolution, without any issues. The problem is that I don't know how, and if possible, I don't know if it would affect anything that I have already done to the map. Wireframe view to show issue:
That's a pretty odd number. In the Terrain object, there is a scale value. By default it's one (1 pixel = 1 meter). Lower the scale to increase the density (ie. scale of 0.5 means 1 pixel = 0.5 meter) Note that heightmaps above 4096x4096 pixels are not supported, it may lead to issues.
I went and measured it this time, and it looks like it wasn't that size at all. I just checked with objects I know the size to and it turns out each square should be 4 metres instead. I really don't understand how any of this works, all I want is to increase the mesh resolution (subdivide) it once to get a higher resolution terrain. I know it is possible because other maps do have a higher resolution terrain at that size, but I don't know how, or if it is possible to take my already edited mesh and convert it to a larger scale. I also cannot find the values you are referring to. Changing the square size just stretches the terrain and the other values don't do anything I want. The values stored withing the json of the terrain don't appear to change anything either. Could it be possible to export the map terrain, scale it to a higher resolution image file (4096 in my case), and re-import it to create a new terrain with a smaller square size (half of the original terrain)? I haven't tested it yet, and am not sure if that would cause any issues with things like decal roads, trees, etc.
I think I have figured it out. I exported the heightmap of the terrain, scaled it to 4096x4096 externally (200% scale), saved it and imported it back into the game as a new terrain object. It appears to have worked, although I need to get textures working and I am not sure if I can entirely replace it without affecting all the decals and things placed on top of it. Additionally, I do not have any image editor that supports 16 bit greyscale png. Do you know of any editor that can do it, preferably free? I have only managed to create 8 bit (per channel) RGB png files, causing a lack of height detail.
That's actually what I ended up using. I finished it yesterday and posted it to my map progress thread, https://www.beamng.com/threads/i-am-making-a-map-development-screenshots.66759/page-2#post-1138883
