Basilisk
Basilisk is the MIT Sustainable Design Lab's building template library project. You can define libraries of building constructions and operational parameters for various types of simulation. Basilisk.Core is the "core" library component; Legacy is for importing our old, deprecated libraries, and the other two are the GUI template editor and its controls library.
Note that revisions prior to 9a8fa883abcecda8dc97b06545a6bda54ed41211 have a fifth project for converting to and from Archsim libraries. For this to work, a copy of Archsim is required, but that's not freely distributable, so it's been stripped from the repo, where it used to live. As a result, that project won't build anymore. If you really want to use it, find a copy of ArchsimLib4Umi.dll and drop it in the "dependencies" folder.