Tangled - think you're right there - the cache either isn't storing that detail or it's a post process which is lost when you render using a cache. It is a small difference granted, but rendering without the cache and surface details on does give that little contact shadow effect which all helps to bed objects into the terrain
I come from from traditional Lighting TD background so I guess I miss having an ambient occlusion pass to bring out detail in scenes (in renderers like PrMan where you can cache quite a detailed ambient occlusion solution).
Also the static scene I'm working on is quite a small for Terragen (80m across) and maybe Terragen isn't really optimised for these kind of scales?
Richard - thanks - the blend mode improves it a little.
Love your site by the way - some lovely images - were you at 422?, met some guys from there a while ago - some very nice Terragen work coming out of that studio.
Attached is a link to the TGD - if you have time to have a look, if you don't, no worries - may be time to bug Mr Fairlclough for a fuller featured ambient occlusion (or perhaps I'm missing something the the AO enviro light?)
https://dl.dropbox.com/u/81475291/gi_surf_details.rar