The Brockley Axe head Three Dimensional Replica

The Brockley Axe 3D replica, is an authentic replication of the worlds largest known, unfinished porcellanite axehead in both digital and 3D printed form. The original axe head dates back to 2,500-4,000 years old (Cooney et al. 2013) and was found on Rahtlin Island, off the North coast of Ireland, by the Green Family. The largest polished Axe heads on record are the Malone Hoard, measuring 20-38cm long and tool large and heavy for practical use (Sheridan, 1986). It has been handed down through recent generations and has been lost and found twice. It represents the origins of craft and repair culture on the island and is irreplaceable. This design-led research aims to replicate the tangible factors of the Brockley Axe head as a publicly accessible artefact. It measures 310mm x 105mm x 80mm with a weight of 2.962kg.

PHOTOGRAMMETRY PROCESS:
The replica was 3D scanned using photogrammetry with the aid of a lightbox, LED lighting and a turntable. Three scans were attempted with the third being highly successful. A Nikon D5300 DSLR camera with a 50mm prime lens was used. The F-Stop was set at f/16 (aperture 1:6), ISO100, exposure bias set to -0.3 step with an exposure of 1/5 second. The scan comprised of 116 photographs. Each image was 6000x4000 pixels at 300 DPI, 24 Bit. Files were saved as sRGB JPG and NEF formats. Reality Capture (now RealityScan) and Agisoft Metascape was used for stitching.

3D PRINT MODEL PROCESS:
The photogrammetry scan was scaled within Autodesk 3DSMAX (2024) to correct the model to real-world scale, using a tolerance of three decimal places within the software restraints minimizing any digital scaling errors from this manual process. The first single volume print, was very successful in its geometric form, but its light weight felt artificial. The second iteration embedded real world weight characteristics embedding lengths for cylindrical brass informed by volume calculations from Columbia Metals online materials calculator (https://columbiametals.com/technical/weight-calculator/). The scanned model was modified using Boolean subtractions to insert the estimated brass inserts. Within Bambu Studio, the 3D print material density digitally calculated as 198.27g for part A and 194.92g for part B. A process of iteration was conducted before final printing of a precise model. The model was constructed in two sections for assembly and the physical artefact verified using digital scales.

GREEN CONSIDERATIONS:
The The digital artefact file was processed using Jawset Postshot and generated as a Gaussian Splat interactive 3D model as an end user interactive experience. Gaussian Splat rendering first emerged as 'SPLATting' (Westover, 1991) but only came into effective use in 2023. It is an emerging technology that we discovered has significant carbon footprint efficiencies. In the case of hte Brockley Axe, a high definition Gaussian Splat is 13.7mb which is 14% of the energy/carbon footprint of its textured .obj counterpart (96.0mb).

The 3DP artefact was printed using 100% Re-Worked PLA 1.75mm Filament, mixed colour manufactured in the UK, resulting in a dark grey similar to the original axe base colour of porcellanite.

DISSEMINATION:
One replica is within the permanent collection of the Boathouse Museum, Rathlin Island, while the original remains with the Green family. It was first made public at the National Museums of Northern Ireland Late Night (21st Aug 2025: Ulster Museum) and at BEYOND2025, Manchester (24th - 276th Nov. 2025: The Lowry) as a physically interactive artefact making authentic heritage more accessible. The digital artefact is featured within a VR game that replicates the original crafting process of the Axe, co-produced with co-investigator partner, Yellow Design. This was demonstrated at BEYOND2025, NMNI Late Night (2025), NI Science Festival 2024, and Rathlin Sound Festival 2024.