Simulation and calculation

Introduction Simulation

Architects and lighting designers use different methods to convey ideas and technical details and communicate these to those involved in the planning process. Concepts can be visually compared during the design phase in order for decisions to be made prior to construction. Since the 80s the established methods of sketching, model making, sampling and drawings havebeen extended by techniques of digital simulation.

Evaluation and presentation
From the digital sketch through to realistic surfaces and luminaires

Simulation and image processing
Abstraction and swift realisation through digital image processing

Quantitative and qualitative simulation
Physically correct numerical values and aesthetically impressive images

Simulation and reality
The limitations of simulations close to reality

Interaction
Modifications in the lighting design process

Design process
Modelling, definition of materials, illumination and rendering

Light simulation

The light simulation has proven to be a useful tool in the visualisation and verification of the lighting design. Initially, a number of steps are required for the preliminary planning of the rendering: the concept idea and the sketch, the 3D CAD model and the specification of the light sources and surface properties. For professional light simulations, the designer uses specialised software such as 3ds VIZ/Max or DIALux. Most CAD programs are not able to simulate light with physically accuracy.

3D model
Topologies and geometries of models

Surface
Simple and complex settings for shading and texture

Light
Virtual luminaires and daylight simulation

Rendering
Differences between radiosity, photon mapping and ray tracing

Evaluation
Aesthetic appearance, accuracy and calculation speed

Hardware
Processors, main memories and graphics cards

Software
Summary of light simulation programs

Developments
Future improvements in light simulation

Calculations

The planning and design of lighting installations involves a number of technical and economical calculations. Usually, these relate to the average lighting level or the exact illuminance at individual points in the room. In addition, it may be useful to determine the luminance levels in specific areas of the room, the quality features of the lighting such as shadow effects and contrast rendition or the cost of a lighting installation including maintenance cost.

Connected load
Planning based on the number of luminaires and illuminance

Point illuminances
Inverse square law to calculate the illuminance distribution

Maintenance Factor
Taking the reduction of luminous flux into account

UGR method
Evaluation of the visual comfort: Unified Glare Rating

Utilisation factor method
Estimated calculation of lighting installations

Lighting costs
Investment and operating costs of lighting installations

Planning data

The lighting design process requires detailed information to ensure compliance with the standards relating to illuminances and visual comfort. Thus for the simulation programs, luminaire manufacturers provide files that contain data on the lighting technology of the luminaires.

Light simulation
Using virtual luminaires for the planning process

Maintained value
Bases of calculation for maintenance

Planning examples

These planning examples illustrate why light simulations are useful tools in the planning process. Along with the representation of optimised luminaire arrangement, the visualisations also help communicate the design concept. At the same time, the examples give an account of a historical development - from the first use of virtual luminaires to reflector calculations to the representation of dynamic, coloured lighting concepts.