Years ago I looked at a tutorial here about tiling terrains, using the Tile North, Tile South, etc. items in the bottom of the Fractal drop-down in the terrain editor. I've looked over the Bryce tutorials that remain on this site, and the ones linked to by Horo and chohole, and it's not there. Also looked at several other sites, including bryce-tutorials.info, docs.daz3d.com, and even went to tutorial index.com. A Google search doesn't find it, either.
In that absent tutorial, there was one particular number I am missing ... the distance between tiles, center to center.
I found another tutorial on tiling terrains about a year ago, and, once again, I can no longer find that one, either. However, when I found that one, though I failed to write down credits, (author, URL, etc.), I did copy the text to a .TXT file, and saved the images. Of those images, the three I attached here are the absolutely most important ... the order of tiling. Trust me ... the order described in these images is the only way it works right. I learned that the hard way ... a few times.
However, that tutorial did not have that magic number I need. The default size for terrains is 81.92 Bryce units. However, you can't simply place the terrains 81.92 Bryce Units apart. There will be a gap. Currently I have the last image below set at 81.74 BU apart. I can still see the seam where the four terrain tiles in the foreground meet. (There's also a fifth, non-tiled, and stretched out terrain beyond those before the 2D Face I used for clouds. Don't be distracted by that.) I suppose I should mention that I'm stuck with Bryce 5.5 for now, until I have better circumstances. It could be that the reason I can't find that info is; it was fixed in version 7. Couldn't know.
Is 81.74 BU the correct number, and the best I can do? when I move them .01 one direction or the other, the seam is more evident. I could have sworn that I had at least one successful tiled terrain image done in the past, based on that first tutorial I mentioned, where no seam was evident anywhere. I can't "seam" to recreate that.
Of course this is a WIP. That block you see cresting a wave is just a place holder for the Ark I've yet to build. By the way, when I go to build the Ark, what's a Cubit? (Just kidding ... that's an old Bill Cosby joke.)