Hi Everyone,
If you're interested in exporting seamlessly tiled terrain for 3rd party renderers, you may wish to have a look at L3DT Professional v14.11 developmental build 1 (on the Pro downloads page now), which includes a new 'File->Export->Export overlapped tiles' menu option. This feature allows you to export any map layer as a set of ovelapping tiles, where each tile contains one extra row/column of data taken from the first row/column of the neighbouring tiles. The user guide is here.
Please note that this feature pretty much replaces both the 'Duplicate tile borders' and 'Grow tile size by one' features.
Best regards,
Aaron.
PS: I don't expect to make any further changes before L3DT release 14.1X, so if you're eager to get the next release early, you can get it by downloading this developmental build.