Ok, now I have a new problem. I sent a render through twice (it completed twice) and I got 2 slightly different renderings. Now I know that Terragen isn't a true ray-tracer (which I think is a strength actually), so maybe these kinds of quirks are expected, but I would like to know all the same. If it was just a little variation in light or colour, I wouldn't mind but in this case, the distortion was fairly obvious.
And for the record, GISD is off.
Any thoughts?
I think this is probably the GI. It doesn't render exactly the same between renders. The differences are exaggerated when you have low quality settings for your GI - mainly it's affected by GI cache detail and GI sample quality. Increasing both of these settings is likely to produce more consistent results.
If you have a scene where you are not going to make any big changes from now on and want to 'freeze' the GI solution, you can write to a GI cache file and then use that for all subsequent renders. However, this capability is only available in Terragen 2 Deep Edition, Terragen 3 Creative + Animation, Terragen 3 Professional and Terragen 3 Professional + Animation.
Matt
Thanks, Matt. I'll try it out.