The site—a constrained mews property—presented extremely tight spatial tolerances. Inspired by spectacular Baroque works such as Francesco Borromini’s (1599-1667) 16th century Palazzo Spada, the original design concept by Archetypes Design ingeniously adopted a principle of forced perspective to counteract the limited space. By creating a series of intersected vaulted ceilings that gradually decrease in scale, combined with a sloping floor, the design manipulates visual perception to create a sense of liturgical depth far greater than reality.

While visually compelling, this geometry presented a formidable challenge for traditional construction methods. The ceiling comprised a complex, intersected vaulted structure of varying scales, transitioning into a feature dome via a double-curved penditive and conical drum geometries. Realising this manually on-site would have been prohibitively time-consuming, costly, and prone to significant inaccuracies.

To translate the continuous curves of the ceiling into a structure that could be manufactured efficiently, we developed a lightweight waffle structure system.

1. Rationalisation:

We extracted the desired ceiling surface from the digital model and sliced it into a grid of interlocking ribs within the size limits of standard plywood sheets and safe handling on site.

2. Optimisation:

The resulting structure consisted of approximately 230 unique sections. Through computational analysis, we reduced unique instances where possible and algorithmic packing scripts minimise material waste and fabrication time.

3. Unrolled Curvature:

Utilising the softwares capability of flattening complex curves surfaces much like sewing patterns, the refined geometry could then be translated into 3D reality utilising 2D Aeroply templates, minimising material waste compared with alternative methods.

4. CNC Fabrication:

Patalab extracted flattened, precisely labelled fabrication files directly from the 3D environment for the fabricator’s to finally process through their CNC (Computer Numerical Control) machines.

5. Site Assembly:

The prefabricated kit-of-parts is then efficiently assembled on site in manageable waffle structure sub-sections, with the Aeroply sheets then tying everything together and forming a robust and geometrically accurate base to receive the final finish.

This workflow shifted the complexity away from the construction site and into the digital domain. Instead of weeks of manual templating, cutting, and shimming on site, pre-fabricated interlocking sections were assembled in a matter of days. The inherent precision of the CNC-cut joints created a self-jigging structure that ensured perfect alignment, meeting the project’s tight tolerances.

The geometry culminates in a feature dome that filters natural and artificial light. For this element, traditional timber framing was insufficient to achieve the intricate detail required, whilst sculpting would prove too costly and time-consuming.

Forming this crowning piece are 432 voussoirs – 36 repeating rows of 12 prismatic shells that gradually reduce in size to form a fractal pattern. In order to realise the pieces within the project constraints, these components were 3D printed, allowing for geometries that would be impossible to mill or cast economically. The result is a lightweight, highly detailed luminous sculpture that crowns the spiritual space.

The St John of Rila project demonstrates that complex geometry need not result in complex construction management. By leveraging Patalab’s expertise in digital fabrication and 3D modelling, we enabled the delivery of a high-precision architectural landmark within a tight timeframe.

We successfully transformed a logistical challenge into a seamless assembly process, proving that with the right digital tools, even the most intricate designs are achievable.