Optimising workflows and proposal of a standard in surveying of deco- rative heritage elements (The Royal Alcazar of Seville, Spain)

Abstract

This research is the result of two multidisciplinary projects funded by the Spanish Ministry of Science, Innovation, and Universities: for the development and evaluation of models of durability and preventive conservation of the plasterwork panels located in The Royal Alcázar of Seville (RAS); and for the optimisation of workflows and proposal of standards in heritage 3D graphic surveys. The development of a durability model in decorative plasterwork panels with marked relief geometries requires, as a previous step, the quantification of the relationship between their spatial and projected areas (established as the Relief Surface Coefficient, RSC), based on accurate three-dimensional models. The main purpose of this coefficient is to provide, from the 2D surface of these elements, a parameter of easy quantification and sufficient accuracy that allows approximation, with a known deviation, of the true cost of the application on these elements of certain conservation and maintenance treatments. In its procurement, the search for a balance between accuracy, data capture process, and post-processing times has enabled the optimisation of the associated workflows and the adoption of a standard of scan resolution to obtain the RSC with low deviations in relief geometries. In order to obtain a high-precision 3D model of the plasterwork panels analysed, the EinScan Pro 2X Plus handheld multifunctional scanner from the Shining 3D company has been employed, which uses an LED light-emitting source. The preliminary work, carried out in a laboratory on a panel of decorative plasterwork (842x394 mm) and subsequently tested on other decorative plasterwork panels located at RAS, has enabled the exhaustive evaluation and optimisation of settings for the standardisation of surveying parameters and workflows associated with obtaining the RSC coefficient.