More about EnergyPlus and DOE-2.2

[hq.cheng]

It was said that Insight uses EnergyPlus & DOE-2.2 as simulation engines. But another saying is that EnergyPlus is developed based on DOE-2. Idk much about these two engines, and the official documentation is so long.... Can anyone briefly introduce the relationship between these two? 

[michel_martinss]

Energy Plus is the union of two tools: DOE-2 and BLAST. This is the main relationship between them. That's why Autodesk puts it this way.