UNIQUE FORMS OF CONTINUITY IN SPACE
Sculpted in 1913. The original plaster still exists in the Museu de Arte Contemporânea in São Paulo, Brazil, but it has been heavily restored over the years.
Back to basics
Unique Forms of Continuity in Space started out as a plaster. There is no known record of Boccioni himself wanting to cast any of his plaster sculptures in metal during his lifetime, so the fact that Unique Forms of Continuity in Space is today almost universally represented as a bronze sculpture is not according to his wishes. F.T. Marinetti was the first to cast the work in bronze in 1933. His aim was to better preserve it for posterity, since the plaster had already started to deteriorate. To date, 18 bronze copies have been cast, eleven of which are copies of already existing bronzes (so called surmoulages).
Boccioni's original 1913 plaster Unique Forms of Continuity in Space still exists and is housed at the Museu de Arte Contemporânea da Universidade de São Paulo (MAC USP) in Brazil. Historical photos reveal that the plaster has changed its appearance over time. This is the unfortunate result of multiple restoration efforts (in 1960, 1971 and 1986) to patch up cracks and damages caused by wear and transport between museums and exhibitions. These alterations are visible in the plaster and even more pronounced in various bronze casts worldwide. While minor differences can result from the bronze casting process (details changed or even lost due to the bronze shrinking as it cools), the significant deviations in the first 1933 cast — made before the restorations — are particularly puzzling. Comparative 3D scans (Magalhães and Zuffo, 2017) show that the Milan bronze closely matches the current MAC USP plaster. However, the absence of photos from the 1933 casting process leaves it unclear whether the plaster was altered before casting or if the changes stem solely from the bronze shrinkage. Further research is needed to investigate this.
In order to match Unique Forms of Continuity in Space more closely with the reconstructed striding sculptures, it was therefore felt necessary to make a photogrammetric copy (essentially a 3D scan) of the bronze version, then digitally “reverse engineer” it back to its original state with the help of the 1913 photographs of the plaster.
The London Tate Modern bronze copy (cast from the MAC USP plaster in 1972) was digitised in high resolution and used as a starting point for the process (2). An in-depth analysis and careful comparison of the 1913 photographs (3a and 3b) with corresponding ones of the Tate Modern bronze (4) provided the information needed for making the necessary sculptural changes in the 3D software. At this stage, it was discovered that the bronze's upper torso is slightly tilted to the left compared to the 1913 photographs. It therefore seems that the casting was done in two parts that were later combined. Overall, the emerging 1913 Unique Forms of Continuity in Space is much tauter and has sharper defined features than the restored plaster, not to mention the bronzes (5).
A small 1:4 scale 3D print of this reconstruction was exhibited at Estorick Collection in 2019. It is currently the closest existing approximation to Boccioni's original conception of Unique Forms of Continuity in Space, and a full-scale version will be 3D printed in late 2022.
References:
Magalhães, A. G., & Zuffo, M. K. (2017). Aquisição e avaliação 3D da escultura Formas Únicas da Continuidade no Espaço, de Umberto Boccioni. Revista USP, (110), 86-103. https://doi.org/10.11606/issn.2316-9036.v0i110p86-103
[Published April 2020]
UPDATE
A revised full-scale version of Unique Forms of Continuity in Space has been 3D printed and assembled (6).
[Published December 2022]

1.
1913 plaster
1933 Milan cast
2.

3a.

3b.

4.

5.
6.