ok grinneh
there is a way to do it. i've used bryce 5 to make an .hmp file or height map.
now i know it doesn't nativly export them but u can export the images. one in black and white for telling it the height. basically the whiter the higher the landscape. and then u need to export the textured image as the overlay.
i can't quiet remember exatly how to do that but i have done it.
and i used the modeling tool that somes with 3d games studio as it allows to export to .hmp if u import the black and white image.
i bet thers some other ones out there that will do it alot better though as the ones i made tended to look cheep and needed a lot of altering
hope that help a bit
(just upgraded) system specs: AMD XP 3000+, 512Mb DDR333, nvidia ge-force FX 5600 128MB, 1x8Gb & 1x40Gb HHD, 52x CD drive, DVD+RW 4x, Sound Blaster 128.... all in a Nokia 8310 case :0D