An Integrated Scalable Lighting Simulation Tool

Lighting simulation contribute readily to the synthesis of high performance lighting designs. Unfortunately there exist several issues impeding the pervasive use of lighting simulation, including: (1) Most of the time in preparing lighting simulations is spent towards the input of existing but non-interoperable information between different tools. (2) Lighting simulation tools do not complement integrated building design processes where the design solution is progressively developed in multiple disciplines concurrently; lighting simulation tools require design information (attributes) that may not yet be defined, and is non-interoperable with other tools. (3) Disparate tools with vastly different technical approaches available for different stages of the building design process do not allow consistent or meaningful performance comparisons between design versions, and similarly makes design performance progress tracking between design versions difficult. (4) Lighting simulation tools provide radiance and irradiance values as simulation results, and much time and manual effort is required to process these results into operative information, information that is directly applicable in making design decisions. (5) Lighting simulation tools employ outdated rendering1 techniques that are inadequate in evaluating highly-reflected irradiance2, a typical feature in high performance building designs.;While there remain other shortcomings in lighting simulation tools as identified by contemporary research3, the issues above relate closely to the overall effort and time-cost factors attributed to using simulation tools, which has been consistently identified4 as obstacles towards using simulation tools. This research seeks to reduce the effort and time-cost required to conduct lighting simulation by addressing the issues above. Case studies of actual design scenarios are used to establish quantitatively the effort and time costs baselines for comparison.;The effort and time reduction goal is structured as the following objectives in a new lighting design support tool: (1) Reduce the time and effort to set up and conduct lighting simulation by using interoperable information (building information models) from design modeling tools. (2) Complement integrated design processes by supporting design models of varying completeness 5, in a format that is interoperable with tools from other disciplines in the design team. All information, including assumptions, must be consistent across all disciplines. (3) Provide ability to use performance metrics and consistent technical approaches throughout design stages, regardless of completeness of design model. (4) Provide operative information with minimum user effort. (5) Implement a first principle-based rendering technique that handles high performance building designs well, and produce simulation results within reasonable time constraints.;By meeting these objectives, the new lighting design tool is able to automate much of the previously manual, time-consuming, and disparate efforts in lighting simulation, thus reducing the effort and time-cost. By sharing interoperable information with other tools across the design team, the new lighting design tool is integrated. The new tool is also scalable in being able to support models of varying completeness throughout all design stages.;;1 Rendering commonly refers to the process of generating computer images from computer models of three-dimensional objects. In lighting simulation, the objective is to compute physically-accurate radiance and irradiance values (lux and candelas per square meter) within an architecture scene described by some computer model, and these values are then typically presented in the form of two-dimensional bitmap images. Note that renderings can be either photo-realistic or physically-accurate. While the two are not mutually exclusive, most rendering features found in architecture software applications are focused on the former. Rendering, as used in the context of lighting simulation, and the rest of this research, refer to algorithms that produce physically-accurate radiance and irradiance values. 2 See discussion of contemporary tools (Chapter 1.2.5) and implemented rendering techniques (Chapters 4.1 and 4.2). Highly-reflected irradiance occurs with the use of diffuse lighting strategies, and light redirecting devices such as light- wells, tubes, and shelves, which are common in contemporary high performance, or green buildings. 3 See literature review of research on development of performance modeling tools (Chapter 2.1.1), industry surveys on use of simulation tools (Chapter 2.1.2), and assessment of lighting simulation tools (Chapter 2.1.3). 4 All the reviewed research (Footnote 1, Chapter 2.1.1, Chapter 2.1.2, and 2.1.3) highlight the time-consuming and difficult nature of manually preparing simulation inputs from non-interoperable data, and translating the simulation results to operative information. Research on the development of performance modeling tools (Chapter 2.1.1) and assessment of lighting simulation tools (Chapter 2.1.3) state this effort and time-cost issue explicitly, whereas industry surveys (Chapter 2.1.2) do so implicitly via the respondents' opinions that modeling involves cost and efforts beyond project budgets and have output that are difficult to interpret and apply in design decision making, as well as the respondents' interest in automated code checking technology. 5 A complete model is defined in this research as one where all attributes, as defined and required for the calculation of performance metrics, and lighting simulation, are explicitly defined.