D Flowgraph GUI Interface

[D.Rex via Digitalmars-d]

Howdy,

I am embarking on a project to create a Flowgraph (node based) 
GUI interface, much like Blender's Node Editor or Unreal ENgine 
4's Blueprint System, for other future projects, I have been 
looking around for many months now on tutorials but I can never 
quite find anything.  I was wondering if anyone could point me to 
a good starting point/tutorial for such an interface.

one of the projects I am endeavoring to work on is a visual 
node-based scripting system for Windows Command Prompt and Linux 
Shell script editing.

I have tried a few things in a few different languages (like 
java) but I really like D as a language, and want this interface 
to be written in it.

Cheers!