How to generate & extract surface area for many shapes given DEM

[tracingcorals]

Hello,

I have read many other help topics & I am still a bit confused, so I appreciate any insight here.. I am working to extract the surface area of corals within a survey area. I have imported a DEM (not created in Agisoft) and a shapefile (of many coral tracings created in Arc) into an Agisoft Metashape project successfully. My question is at this point, what is the best way to calculate their surface area? Is the "area projected onto the best fitting plane of a polygon" a proxy for this? Is there a different tool to calculate surface area besides 'Measure'? And how do I add the surface area metrics measured by Agisoft back into the shapefile's property table & export it for analysis?

Thanks!