Hi Ben, Roassal offers a low level API with which you should be able to do anything. You use this API when you have instantiating ROView, ROElement, ROEdge. The inconvenient, is that it is quite verbose. The builder offers a higher level API. ROMondrianViewBuilder defines a domain specific language that is very convenient to define simple static views. By "simple" I mean without animation, interactive hiding elements, resizing and no semantic zoom. This language is backward compatible with Mondrian. From what I got from people feedback, is that this Mondrian language is complicated to use and people feel it involves a lot of voodoo magic, especially regarding edges manipulation. Once you get used to this language, you realize it is incredibly expressive. So, which one you should use? You can use both, which is, in my opinion, a really cool feature of Roassal. You create a ROView, gives it to a builder (ROMondrianViewBuilder class>>view:) and build your view using Mondrian. After that, you can fiddle with low level things. My vision for Roassal is to offer a platform on which anyone can easily experiment and produce new domain specific languages. You may wonder why one may want to define its own domain specific language? The current Mondrian DSL is not able to do complicated things that involves animations. Consider the following example: http://peoplemov.in/#f_HR Cool visu isn't it? However Mondrian is not made to render such a thing. We need a different specific language. This is what Roassal should support. Cheers, Alexandre On Aug 20, 2012, at 9:26 AM, Ben Coman <btc(a)openInWorld.com> wrote: -- _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: Alexandre Bergel http://www.bergel.eu ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.