Are you running Windows 95/98? I find under Windows 98 that I can only load a model no larger than 15-17 meg in .obj format, And ME seems to be worse. 256 Meg on a 850 Mhz laptop made no improvement in maximum loadable filesize. Under Windows NT, The limit is more like 120 Meg (with 128 Meg of RAM)(I successfully loaded 117 Meg Onyx tree model, failed at 135 meg...) Bryce 4 is better than Bryce 3, and I haven't tried to find the limits yet in Bryce 5, mostly because Bryce 5 has native trees with real curved leaves.