www.dad.net.au

The UI is terrible, concept is good, but it is basically a ported node graph - system defined by nodes and interconnections.

I have used it to design entire industrial plant facilities.

I have been working on a Qt version on and off for a while, not sure if it will be personal use or see the light of day.

RapidHarness is good, although it's paid. If you're at a university, they sometimes provide educational licenses for free if you ask nicely.

RapidHarness is good, although it's paid. If you're at a university, they sometimes provide educational licenses for free if you ask nicely.

Do you mean like a block diagram? You might have to be more specific about the type of job you're working on.