## 5 Conclusions  
With exception to the photogrammetry software used (for which there are open-source alternatives), the methods employed here utilize open-source toolkits for preparation, analysis, and presentation of the 3D data. These data are published in an open repository where they can be downloaded and viewed. The technique discussed also enables others to re-run the interpolation tools we used in the paper and replicate the results of the analysis. The results here highlight the need to consider multiple lines of evidence when examining composite objects in general, and bronzes in particular, and also the benefits of considering assays holistically and in a 3D context. Alone, the pXRF results can be presented on a table, and conclusions, such as those reached here, could have been achievedwithout the 3D interpolation. However, we would argue that such results are enhanced and rendered more accessible through their presentation on a 3D model. Most notably, the relationship between the points assayed as well as their relative positions on the artefact are often missed or can be misinterpreted when presented as simple tabular data. For instance, when considering the helmet discussed in this paper, the evident variability in the readings can be contrasted with the visible structuring of the helmet, its two halves and two plates, making analysis and interpretation much easier. Variability within and across different pieces is quickly and clearly evident, revealing that the most substantial variations likely relate to patination and not production. Comparisons using the Compton scatter measurements, both amongst the readings themselves and across calibrated elements, also highlight areas where, particularly on an item as thin as the helmet (c. 0.5 mm in places), additional care should be taken in interpretation due to the increased density which, at least in this instance, likely relates to thickness. A particular benefit to the interpolation approach we propose is that it provides a visual aspect to the data which integrates them with their parent object. It also enables them to be readily compared to other visual analyses. For example, when compared against the DStretch models, another line of evidence is provided by which to interpret both the assays and the wider artefact. The photogrammetric model itself is used as a base in these cases as opposed to being limited to only a visualisation element. As 3D data and publishing become more integrated and complex (see [30]) so too do the possibilities for combining techniques that have traditionally not been considered complementary. Conceptualization, J.E. and J.A. ; Methodology, J.E., A.M. and J.A. ; Software, J.E. ; Validation, J.E., A.M. and J.A. ; Formal Analysis, J.E., A.M.; Investigation, J.E. ; Resources, J.E. and J.A. ; Data Curation, J.E. ; Writing--Original Draft Preparation, J.E., A.M., N.B., J.A. ; Writing--Review & Editing, J.E., A.M., N.B. and J.A. ; Visualization, J.E. ; Supervision, J.A. ; Project Administration, J.A. ; Funding Acquisition, J.A. All authors have read and agreed to the published version of the manuscript. This study was funded by the Royal Society of New Zealand Marsden Fund project 'Blood and Money: The \"Military Industrial Complex\" of Archaic Central Italy\" [17-UOA-136] awarded to [PERSON]. Not applicable. The calibrated assays used in this study are presented in Table 1. Photogrammetric models, decorrelation stretching textures, calibrated assays, and assay locations are available at: [PERSON], [PERSON], [PERSON] and [PERSON] (2021c) '3D and assay data published in 'XRF and 3D modelling on a composite Etruscan helmet\". Zenodo doi:10.5281/zenodo.5160531. Thanks to [PERSON] for comments on this paper, [PERSON] for advice on implementing the scripts, and [PERSON] for assistance with the preparation of the figures.