logo Lightsolve Lightsolve
daylight at the service of architecture

logo LIPID logo EPFL

General Principle

The general approach for Lightsolve is to inform well-balanced daylight design during early design stages through an interactive visualization and a pro-active, guided improvement of full- year time-varied daylighting performance. One of the underlying principles in terms of how daylighting performance is evaluated is to make it specific to the user’s own performance objectives and to his or her areas of interest, as well as to combine a synthetic perspective of full-year data with a visual impression of what the space looks like over time.

Manual & User Manual

User Manual 2016: Lightsolve Wiki @ EPFL

Quick Start Guide 2016 [.pdf]

Windows version
Please make sure your computer fills the requirements in terms of GPU, using our Hardware Checker
Download the Lightsolve Hardware Checker [self extracting archive]

Also make sure you installed the Microsoft Visual C++ 2010 Runtime package, it can be downloaded here :
Get the Visual C++ 2010 Runtime package [official page]

This version was developed on a Desktop PC 3.8 GHz Intel Core i7-2600K, 16GB RAM, NVIDIA GeForce GTX 980 4096 MB
Download the Lightsolve 2016 Windows installer [.exe]

Recommended system requirements: Lightsolve is taking advantage of:

LIPID OBJ Exporter SketchUp Extension
In order to enable the free version of SketchUp to interoperate with Radiance (in our case, inside Lightsolve) we developed an extension to export your models to the Wavefront OBJ file format. It is available for free on the SketchUp Extension Warehouse

Lightsolve is a software developed by LIPID EPFL for academic and research purposes. The application bundle is provided for free, "as is" and without warranties to students, researchers and practitioners interested in testing the tool.

Lightsolve provides likely illuminance values in reasonable time. It allows daylighting performance to be assessed by students during one exercice session, rather than a dedicated project. The complex process of preparing an early design model for daylight simulations is made easy and the ray-tracing times are made acceptable thanks to the modern graphic acceleration hardware and libraries (OptiX) made available by NVidia.
Finally, as the OptiX based engine is not yet validated and is not yet to be used for research purposes, it is possible to switch the simulation engine to Radiance, and to intercept and modify the flux of commands and data that is sent to it.

Screenshots & Animations

Instant Goal Based Performance - Illuminance Instant Goal Based Performance - Illuminance Instant Goal Based Performance - Illuminance Annual Goal Based Performance - Illuminance Detailed Goal Based Performance - Illuminance Detailed Goal Based Performance - Illuminance Annual Goal Based Performance - Illuminance Detailed Goal Based Performance - Constrast All sensors at a glance, instant All sensors at a glance, annual view Lightsolve: from modeling to simulation.

Related Publications

  • Unweaving the human response in daylight design
    M. Andersen
    Building and Environment (ISSN: 0360-1323), vol. 91, p. 101-117, 2015
    [@ infoscience]

  • Measuring the Dynamics of Contrast & Daylight Variability in Architecture: A Proof of Concept Methodology
    S. F. Rockcastle and M. Andersen
    Building and Environment (ISSN: 0360-1323), vol. 81, p. 320-333, 2014
    [@ infoscience]

  • Interactive expert support for early stage full-year daylighting design: a user's perspective on Lightsolve
    M. Andersen, J. M. L. Gagne and S. Kleindienst
    Automation in Construction, vol. 35, p. 338-352, 2013
    [@ infoscience]

  • Comprehensive Annual Daylight Design through a Goal-Based Approach
    S. Kleindienst and M. Andersen
    Building Research & Information, vol. 40, num. 2, p. 154-173, 2013
    [@ infoscience]

  • An Interactive Expert System for Daylighting Design Exploration
    J. M. L. Gagne, M. Andersen and L. K. Norford
    Building and Environment (ISSN: 0360-1323), vol. 46, num. 11, p. 2351-2364, 2011
    [@ infoscience]

  • Graphical Representation of Climate-Based Daylight Performance to Support Architectural Design
    S. Kleindienst, M. Bodart and M. Andersen
    LEUKOS 2008 – The Journal of the Illuminating Engineering Society of North America, vol. 5, num. 1, p. 39-61, 2008
    [@ infoscience]

  • An intuitive daylighting performance analysis and optimization approach
    M. Andersen, S. Kleindienst, L. Yi, J. Lee, M. Bodart and B. Cutler
    Building Research And Information (ISSN: 0961-3218), vol. 36, num. 6, p. 593-607, 2008
    [@ infoscience]


To get help using Lightsolve write to Technical Assistance.

For any suggestions, noticed issues, improvements, etc. write to User Feedback.

For general inquiries or more information about the development team, please visit:
Interdisciplinary Laboratory of Performance-Integrated Design (LIPID)
LE 1 110 (LE Building)
Station 18
CH-1015 Lausanne