The CAD industry is incestuous, with people wandering from firm to firm, starting new ones, joining old ones. The software itself tends to work and look the same, no matter the source -- with a few exceptions. Even without knowing the inside story, it is possible to speculate over the lines of heritage. Sometimes we get it wrong.
One factoid concerns the source of Revit, which seemingly came out of nowhere, helped by $50+ million in funding, and whose founders came from PTC -- a firm solidly based in MCAD, not AEC. (A factoid is speculation reported often enough to become accepted as fact.) The lineage of Revit was traced back to Sonata, which is not true.
Revit co-founder Irwin Jungreis writes to correct the factoid:
The article about Bricsys in the May 1 issue of upFront.eZine stated that Revit's "code pedigree goes back to Pro/Reflex and before that to grand-daddy Sonata".
In fact, neither the concepts nor the code base of Revit were derived from Pro/Reflex. The most recent issue of AEC magazine included my letter revealing the real relationship between Revit and Pro/Reflex. It may be seen here: http://aecmag.com/59-features/1352-celebrating-the-history-of-bim.
I hope you will find it interesting and informative.
It is worthwhile reading the details in AEC magazine of how Revit came about. Here are some highlights:
"Soon after leaving, we agreed to provide PTC consulting services in exchange for a non-exclusive development license to Reflex, which PTC had recently acquired [under the name of Pro/Reflex].
"After receiving several hours of instruction in the software architecture of Reflex from Reflex developers, we decided not to use it as our starting point, because of several important differences at the very foundations of the software. At that point, we put it aside and never looked at it again.
"Reflex components are created using a specialized programming language (VEL), whereas Revit components are created in a graphical family editor.
"No code from Reflex was used... In fact, we found the most inspiration from a $50 product called 3D Home Architect (a home version of Chief Architect), which had a clean, simple user interface."