These are my terrain settings, yes I know they are large, but they should generate layers without issue, and they do provided I use 10m/pixel resolutions
MapFrame Properties:
Grid size: 4096 x 4096
Cell Size(m): 10.00
Terrain Size(m): 40960.000
Satellite/Surface (mask) source images:
Size(px): 20480 x 20480 <--- Will not let me define 40960(1m/pixel), even though I have 4x20480 image's tiled in my mapframe.
Resolution (m/px): 2.000000
Satellite/Surface (mask) tiles:
Size (px): 2048 x 2048 <-- Will not generate at anything below this setting (Do you know how difficult it is to have a detailed map when each one of your surface tiles is 2km in game?)
Desired Overlap (px): 16
Texture Layer: 40.00 x 40.00 <-- Just about every forum post & tutorial stipulates not to deviate from this setting, is it will create errors - messed up maps (tartan & other issues)
Source Files Properties:
Heightfield = 4096x10m grid generated with L3DT, saved as an .ASC
Satellite Source Images = 4 x 20480(TIFF) images tiled into a 40960x40960 Sat-mask
Surface Mask Source Images = 4 x 20480(TIFF) images tiled into a 40960x40960 Surface-mask.
Normals Mask Source Images = 4 x 20480 (TIFF) images tiled into a 40960x40960 Normal Mask.
NB - I have tried with just about every format TB will accept - BMP/PNG/TIFF/XYZ/ASC - I had to, to get beyond the 2GB limit on importing files when I generated 40960x40960 single source images - so it is definately not a source image issue, and definately IS a mapframe properties / layer generation / grid issue.
The only time my map has generated layers without issue was with 10m/pixel resolution Sat + Surface mask source images, which on a 41km terrain is a shockingly bad level of detail.
There are quite a few people in the Terrain builders Skype group reporting issues like the above, from small terrains to large and is prohibiting a lot of people from working further on thier terrains.