Hi,
We've been using OmniGraffle for all of our diagram work, for which this is the best tool out there!
We've also been investigating applications on the Mac that could create our Systems Thinking maps, much like Vensim does on Windows. There used to be a Mac version of Vensim, but this only works on MacOS X 'Classic'. Not an option.
Now we would like to use OmniGraffe to draw our reinforcing and balancing loops. But initial tests proved that this is quite time-consuming using OmniGraffle, just because we need a particular kind of arrows (See image attached), which do not come standard with OmniGraffle. Using stencils is not a workable option.
System thinkers use a particular kind of arrow, to indicate the type of relationship:
-->+ or -->s (meaning that the relationship is 'the same')
and
-->- or -->o (meaning that the relationship is 'the opposite').
We're sure that this is just a small thing to add to the application's standard arrows. It would surely help us a great deal forward, and open up a huge potential for a market niche with system thinkers world-wide.
Thanks,
Stephan