The overall development of DAYSIM has been coordinated by Christoph Reinhart since 1998. The global illumination calculation in DAYSIM is based on the RADIANCE backward raytracer. Past and ongoing development work for DAYSIM has been conducted at

• Fraunhofer Institute for Solar Energy Systems (ISE)
• Harvard University
• Massachusetts Institute of Technology (MIT)
  
• National Research Council (NRC) Canada

Individual simulation modules within DAYSIM were developed as follows:

2012 Multiple independent Shading and Lighting groups were implemented at MIT into the Daysim ds_electric_lighting program to support the modeling of complex dynamic facade systems and multiple zone lighting control systems.

2010 A new DAYSIM subprogram called gen_dgp_profile was developed at the Fraunhofer ISE to conduct annual glare simulations within DAYSIM based on the daylight glare probability concept.

2009 Daysim and 3dsMax simulation results were validated at Harvard University against measurements of five facade systems collected at the NRC Canada.

2006 Daysim simulations of a translucent glazing system were validated based on measurements conducted at MIT and the NRC Canada.

2004 The Lightswitch occupant behavior model was developed and implemented into the Daysim ds_electric_lighting subprogram at the National Research Council Canada based on field study data collected at the Fraunhofer ISE.

2003 A modified version of the RADIANCE program rtrace that calculates a set of daylight coefficients using either the traditional RADIANCE approach or PhotonMap forward raytraing was programmed at the Fraunhofer ISE.

2003 An early version of DAYSIM's JAVA graphical user interface was programmed at the NRC Canada.

2001: The DAYSIM subprogram to model the short-time step dynamics on indoor illuminance was developed and implemented at the Fraunhofer ISE.

2001: DAYSIM's dynamic daylight simulation module to simulate annual illuminance profiles was developed and implemented at the Fraunhofer ISE.