After several years - almost 20 - I've recently met an old friend who is a software engineer.
He mainly write software to project modular furniture. Talking about the matter, he told me he's developed Webriko, a web app which helps him to "see his code".
He uses it as his main tool for his day by day job, he also told me he thinks that it's such a useful piece of software but he's too lazy to promote it or show it to people.
So here I am, introducing you to Webriko. Perhaps it's really great and it comes useful to you too.
Free software, no registration required. Nothing's required actually.
http://webriko.com/node-based-programming/en/overview.html