World Machine by Stephen Schmitt is a piece of software that can help you generate various types of terrains that can be used by artists, game developers, visual effect studios and more. Sadly, there is no official build of World Machine for Mac, therefore, you will have to use other applications to generate the desired terrains. Here is a list of possible replacements for World Machine for Mac.
Feel free to add any alternative to World Machine for Mac that you know of.
Suggest Alternatives
Bryce won't work on anything later than Snow Leopard (Mac 10.6), so unless you can run that OS I wouldn't bother with this one, until DAZ can get their act together and recompile...