3D Design Bureau

How to Conduct a Successful Daylight & Sunlight Assessment

There are various stages involved in the production of a comprehensive daylight and sunlight assessment. From building the detailed analytical 3D model to writing the final report, a huge amount of work and understanding of data takes place during the course of a project.

The following is an overview of best practices for daylight and sunlight assessment methodology.

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The 3D Analytical Model:

The foundation for an accurate daylight and sunlight assessment is the digital 3D analytical model. It should include the proposed development and its surrounding existing context as detailed and as accurately as possible.

Proposed buildings and site/landscaping design should be modeled from architectural and landscaping drawings. As standard practice, a combination of survey information, aerial photography, available online photography, and/or ordnance survey information should be used to model the surrounding context and assessed buildings.

There are at least two model states that are used for daylight and sunlight assessments.

Baseline Model State:

The baseline model state reflects the existing environment. It should include the surrounding context and the subject site in its current standing. This includes any structures that are to be demolished as part of the planning application. Existing trees should be included.

Proposed Model State:

The proposed model state reflects the subject site if the development is built as proposed. This includes the demolishing of structures, landscaping, etc. The proposed landscape plan, provided by the landscape architect should be used to include proposed trees to ensure that none have an impact on the levels of daylight and sunlight inside the proposed habitable rooms.

Cumulative Model State:

The cumulative proposed model state reflects the subject site if the development is built as proposed AND any proposed developments in close proximity to the subject site that have received planning permission. This includes the demolishing of structures, landscaping, etc. Proposed trees should also be included in this state and used accordingly in the relevant studies.

3D Design Bureau create their 3D models for daylight and sunlight assessment using Autodesk Revit. The same 3D model is used for computer-generated imagery for the planning application. This proves to be very advantageous when changes are required to the design of a scheme due to issues that arise during the course of a daylight and sunlight assessment.

It is important to note that since the release of the BRE 209 (2022) the inclusion of trees in the analytical 3D model is required. This includes both existing and proposed deciduous and evergreen trees. To understand which type of tree should be included in each type of assessment, ‘Impact Assessment’ and ‘Scheme Performance’,  visit A professional take on Trees for Daylight and Sunlight assessments.

Running the assessment:

The assessment part of the project is where all the data is captured by our analysts for all metrics of the ‘Impact Assessment’ and ‘Scheme Performance’. The analytical 3D model is taken into specialist daylight and sunlight software with all data collected for each assessment (VSC, A/WPSH, SOG, SDA, SE, NSL – See terminology) The assessment data is then reviewed to understand how the scheme is performing on itself and on its neighboring properties and environment. A full set of results should be published and consultation with the client and design team should then take place.

During this consultation period with 3DDB, advice will be given as to how to improve the results where possible. Design changes should be implemented into the digital 3D model and reassessment carried out to achieve the highest levels of compliance possible whilst taking into consideration other design and planning factors. See How to Improve Daylight and Sunlight Assessment Results.

Once all results are approved and signed off, a full detailed report is written. It is imperative that daylight and sunlight reports include all information about the assessment. If full information is not presented, and a scheme is granted permission, then the application can run the risk of a Judicial Review. This is because it may be deemed that the planning authority gave a grant of permission without having the full set of information to hand.

If you need advice on your project with regard to daylight and sunlight, get in touch with our team who will be more than happy to shed more light on your project! For more information on daylight and sunlight assessments, you can also visit the articles below or book a free presentation with the team by contacting us at info@3ddesignbureau.com or +353 1 2880186.

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Nicholas Polley - Managing Director at 3D Design Bureau


Nicholas Polley
Managing Director
at 3D Design Bureau


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