I'm not sure how the terrains work, but a 4096x4096 terrain seems way unnessary. That's a whole lot of detail there, you'd probably be able to get away with a 512x512 or 1024x1024. But that's you're choice. Terragen for example maxes out at 513x513.
Bigger heightmaps don't make it slower as far as I'm aware as you set the LOD to xx polys.
I create heightmaps by using perlin noise then edit it in a paint program, you usually need to smooth a few edges here and there to reduce LOD pop/morph and it tends to make it looks better, although you do lose a little detail.
Texturing, the way I go about it is by using a 'noise' pattern that is tiled over the whole thing, this just gives a bit of detail when you're up closed, use a grey scale sand texture or something, then multi-texture a big texture stretched over the whole map that gives tonal colour and shadow/light, this works pretty well. Especially for flight sim type stuff that doesn't need close up detail. I wrote a little app called terrain shader 2.0 that creates the big texture based on height, slope, adds lighting and shadows. Although there's still an older version of Terrain Shader that creates light and shadow but no texturing for free download.
Output from Terrain Shader 2.0 rendered in blitz in real time:
My Lander game uses a 512x512 heightmap with a 512x512 texture wrapped over the top of it and I think it gives plenty of detail.
Bigger heightmaps don't make it slower as far as I'm aware as you set the LOD to xx polys.
I create heightmaps by using perlin noise then edit it in a paint program, you usually need to smooth a few edges here and there to reduce LOD pop/morph and it tends to make it looks better, although you do lose a little detail.
Texturing, the way I go about it is by using a 'noise' pattern that is tiled over the whole thing, this just gives a bit of detail when you're up closed, use a grey scale sand texture or something, then multi-texture a big texture stretched over the whole map that gives tonal colour and shadow/light, this works pretty well. Especially for flight sim type stuff that doesn't need close up detail. I wrote a little app called terrain shader 2.0 that creates the big texture based on height, slope, adds lighting and shadows. Although there's still an older version of Terrain Shader that creates light and shadow but no texturing for free download.
Output from Terrain Shader 2.0 rendered in blitz in real time:
My Lander game uses a 512x512 heightmap with a 512x512 texture wrapped over the top of it and I think it gives plenty of detail.