One of our intrepid contributors, tapir, found and fixed a 20 year old flaw in qbsp3, the Quake2 BSP compiler. If you've ever struggled with complex, intricate brushes being mangled by qbsp3, consider adopting this one-line fix:https://github.com/jdolan/quetoo/pull/241/files
This epsilon value specifies the threshold the compiler uses to determine if a vertex requested by a winding is "close enough," or if a new vertex should be allocated. The original value of 0.5 means that no two vertices can be closer than 0.7 units -- they become merged into one. This leads to hairline cracks in brushes pretty often, especially in curved geometry (arches, spherical volumes, etc).
Changing this epsilon to 0.1 fixed numerous errors in several of our more intricately brushed maps. I highly recommend it for other idTech2 projects still kicking out there.