Ladybug and Honeybee are two open source plugins for Grasshopper and Rhinoceros that help explore and evaluate environmental performance. Ladybug imports standard EnergyPlus weather files (.EPW) into Grasshopper and provides a variety of 3D interactive graphics to support the decision-making process during the initial stages of design. Honeybee connects the visual programming environment of Grasshopper to four validated simulation engines - specifically, EnergyPlus, Radiance, Daysim and OpenStudio - which evaluate building energy consumption, comfort, and daylighting (Sadeghipour Roudsari M., Pak M., 2013). These plugins enable a dynamic coupling between the flexible, component-based, visual programming interface of Grasshopper and validated environmental data sets and simulation engines.
Sadeghipour Roudsari, Mostapha; Pak, Michelle, 2013. Ladybug: a parametric environmental plugin for grasshopper to help designers create an environmentally-conscious design. In: Proceedings of the 13th International IBPSA Conference Held in Lyon, France Aug 25–30th. (http://www.ibpsa.org/proceedings/BS2013/p_2499.pdf)