Sunform

--JakePWhite 12:30, 28 Jul 2026 (BST)

SunForm

SunForm is a free, browser-based tool for analysing solar exposure on building models. It imports a building's geometry from an Industry Foundation Classes (IFC) file, calculates how many hours of direct sunlight each surface receives across a chosen day or period, and displays the result as a colour gradient on the three-dimensional model. The tool runs in the web browser and requires no installation and no account.

Background

Understanding how sunlight falls on a building and its surroundings informs decisions on window placement, shading, overheating, the overshadowing of neighbouring property, and the siting of outdoor space. Solar studies are often produced in specialist environmental analysis software, or as part of a full daylight and sunlight assessment, which can require dedicated tools and expertise. SunForm provides a lightweight alternative that works directly from an IFC model, allowing a designer to test solar exposure at an early design stage within a web browser.

The tool was developed by Jake White Architecture, a residential focused architectural practice based in West Sussex.

How it works

The user loads an IFC model and selects a location and a day or period for analysis. SunForm evaluates each surface of the model against the position of the sun through the daylight hours of that period.

Solar position is calculated using the Spencer algorithm, a Fourier-series approximation that returns the sun's declination and the equation of time for a given day of the year. For each point being tested, the tool casts a ray towards the sun and checks whether any other part of the model intersects that ray, using the Möller-Trumbore ray-triangle intersection method. Where the ray reaches the sun unobstructed the point is in sunlight; where it is blocked the point is in shade. Accumulating these results across the period produces a sun-hours value for every surface.

The analysis is applied to all surfaces regardless of orientation, so walls, roofs, soffits and ground planes are treated in the same pass.

Outputs

Results are shown as a continuous colour gradient mapped across the three-dimensional model, so patterns of solar exposure and overshadowing can be read directly on screen.

Limitations

SunForm is a design aid in public Beta. It is not a substitute for a formal daylight and sunlight assessment prepared to a recognised methodology such as the Building Research Establishment (BRE) guidelines, and it does not constitute a right of light analysis. All outputs must be independently verified before they are relied upon.

The tool currently expects the model to be positioned close to the coordinate origin. Georeferenced IFC files placed a long distance from the origin are not yet fully supported.

Technology

SunForm runs in the web browser. The three-dimensional model is displayed using Three.js, with solar exposure mapped across each surface as a per-vertex value.

External links

• SunForm tool: https://jakewhitearchitecture.com/sunform/
• Jake White Architecture: https://jakewhitearchitecture.com