Before a single luminaire is installed, light can already be calculated, compared and made visible.
That sounds like a preview of the finished space.
It is not quite that simple.
A lighting simulation does not show the future. It shows what is likely to happen under a defined set of assumptions.
A digital lighting model can show how much light reaches a work surface.
It can compare distributions. Identify dark edge zones. Analyse daylight. Assess glare risks. Test alternatives against one another.
But its greatest value is not in producing a beautiful image of the finished space.
It makes design decisions testable before they become expensive on site.
Calculation surfaces can provide illuminance, uniformity and other lighting metrics for a defined situation.
Room geometry, luminaires, surfaces and boundary conditions are combined in a digital model in which different variants can be investigated.
Spatial views, false-colour images and renderings help make calculated results readable and understandable for other members of the design team.
Put simply, the software needs two things: a digital model of the space and data describing how light behaves within it.
The model contains information such as room dimensions, openings, luminaire positions and relevant surfaces.
Photometric luminaire data is then added. Formats such as LDT or IES describe, among other things, how a specific luminaire emits light in different directions.
Only from this information can the software calculate how light reaches defined points and surfaces.
Room dimensions, heights, walls, ceilings, openings and relevant built-in elements.
Luminous flux, luminous intensity distribution, optics and beam characteristics of the luminaires.
Reflectance assumptions influence how much light walls, floors and ceilings return into the room.
Windows, orientation, location, shading and the daylight conditions being investigated.
Their position and height determine where the software actually evaluates lighting values.
This is one of the most important characteristics of any simulation.
A highly precise calculation can still be based on an incorrect assumption.
If the ceiling is too bright in the model, more reflected light will be calculated. If the calculation surface is positioned at the wrong height, the result may answer the wrong question. If a different optic is used from the one eventually installed, even the most precise output loses relevance.
Simulation reduces uncertainty. It does not eliminate it.
Is the aim to assess a workplace? A wall? Daylight? Glare? A luminaire option? Without a clear question, it is easy to generate a large amount of data without a clear conclusion.
The geometry should be as detailed as necessary – not necessarily as detailed as possible.
Luminaire data, reflectance values, calculation surfaces and daylight conditions define the parameters of the model.
The model is evaluated. Depending on the question, the output may include numerical results, distribution maps or spatial visualisations.
Positions, optics, luminous fluxes or control zones can be changed and assessed again.
The simulation provides information. The design decision only emerges through interpretation of that information.
The most valuable results of a lighting simulation often look far less spectacular than a photorealistic image.
At Impact Hub Berlin in the CRCLR House, daylight studies formed part of the design process.
The studies investigated how far natural light penetrated into different areas of the floor and where it was no longer sufficient.
The result did not remain inside the simulation.
The daylight analysis influenced spatial decisions and was later used as a basis for organising luminaires into meaningful control groups.
The simulation therefore became more than a representation of the project. It became a tool that changed decisions within the project.
This may be the most important point when reading a lighting simulation.
An average value can be correct. A standard can be fulfilled. A calculation can be mathematically precise.
And yet the design can still miss its actual objective.
Perhaps the work surface is sufficiently bright while faces remain too dark. Perhaps the centre of the room works while the edges fall away. Perhaps the lux values are correct while the ceiling becomes visually too dominant.
The simulation answers the question it was asked. Good lighting design decides which question needs to be asked.
A white ceiling and a dark exposed-concrete ceiling distribute reflected light in completely different ways.
Even a change in the distance between luminaire and surface affects the size and intensity of the light distribution.
If the calculation does not use the intended optic or photometric data, even a precise simulation becomes inaccurate for the actual product.
A value measured on the floor does not automatically answer a question about a desk, a face or a wall.
Daylight changes with time, orientation and external conditions. A snapshot is not automatically a complete lighting strategy.
More geometric detail does not automatically mean more useful information. What matters is whether those details affect the lighting question being investigated.
A realistic rendering is excellent for communicating an idea.
But an image on a screen can appear brighter, more contrast-rich or more dramatic than the real space.
Exposure and image processing are part of the representation.
A calculation surface serves a different purpose. It does not try to look convincing. It tries to evaluate a defined quantity in a traceable way.
A rendering explains. A calculation verifies. Both are valuable – as long as they are not confused.
Distributions.
Variants.
Illuminance levels.
Daylight zones.
Positions.
Optics.
Real reflections.
Surfaces.
Viewing angles.
Glare.
Material behaviour.
Construction details.
Different materials and details were physically tested for the project-specific workplace luminaires at Impact Hub Berlin.
One of the questions was how a perforated material on the underside of the luminaire would influence light transmission and glare.
This is where physical testing complements digital planning.
A simulation can prepare an assumption. A real test reveals how material, light and actual viewing direction interact.
Different positions, optics or quantities of luminaires can be compared under the same conditions.
Illuminance, uniformity and, where relevant, glare can be investigated for specific visual tasks.
Simulations can reveal which areas are already well supplied by natural light and where artificial light needs to supplement it.
A model can reveal where unnecessarily high light levels occur and where output could potentially be reduced.
Not only work surfaces: walls and other relevant surfaces can also be evaluated specifically.
Different daylight and usage zones can provide useful information for later switching and dimming groups.
A simulation can show very precisely what happens under its defined conditions.
But it cannot decide whether a wall should be highlighted in the first place. Whether a space needs more contrast. Which viewing direction matters most architecturally. Or whether a technically possible solution actually suits the architecture.
Those decisions belong to the design process.
Simulation is therefore not a substitute for lighting design. It is one of its most precise testing tools.
The lighting idea emerges from space, use and architecture.
Relevant geometry and assumptions are translated into a digital model.
The question is tested using defined lighting metrics.
Position, optics or lighting strategy are refined based on the results.
Critical details are physically tested where necessary.
In the completed space, aiming, dimming and scenes are adjusted for the final result.
A lighting simulation creates a digital model of a space and calculates how artificial light, daylight or both behave under defined conditions. Geometry, luminaire data, surfaces and calculation planes are among the factors taken into account.
A lighting calculation is the numerical evaluation of defined lighting metrics. Lighting simulation is broader and combines these calculations with a spatial digital model and visual evaluation methods.
Typical inputs include room geometry, luminaire positions, photometric luminaire data, surface assumptions and defined calculation planes. Daylight analysis also requires information such as openings, orientation and location.
LDT and IES are widely used photometric file formats. They contain technical information about how a luminaire distributes light in different directions and can be used in professional lighting design software.
No. It can provide highly precise results for defined assumptions, but the real space contains materials, tolerances, viewing directions and patterns of use that cannot always be modelled completely.
Yes. Daylight simulations can investigate how natural light enters a building depending on room geometry, openings, orientation, location and other parameters.
Not always. Simulation is particularly useful for clearly modelled and measurable questions. With critical materials, bespoke luminaires, glare or complex details, physical testing can provide additional information.
Studio De Schutter combines digital lighting calculations with architectural design, daylight analysis, physical testing and fine-tuning.
Define the questions. Build the models. Calculate alternatives. Read the results. Test the details. Refine the decisions.
So that simulation does more than produce numbers – it enables better decisions.
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