Seems that I'm getting somewhere with this UVAtlas tool - seems it wasn't as complicated as it first looked. Which is nice.
I need to work on the various parameters - seems that the terrain tends to break into a ridiculous number of charts - it'd be better/nicer if I could tweak it to group more triangles together into fewer charts.
One thing I have noticed, by comparison to the trivial texturing...
In trivial texturing, you might have a 1024*1024 texture - and it will use all 1,048,576 pixels in it. My current trials with generating a UVAtlas for a terrain leaves a large amount of empty texture space. The distribution of pixels is much better - but it may well require that (to get similar resolution to the trivial technique) a much larger texture is used.
More on this later, hopefully with some pretty pictures [grin]