[Qgis-user] Add distance to shapefile M

[Andrea Giudiceandrea]

Hi Stewart,
it is not clear to me exactly what to want to achieve. If you want to 
calculate the 3d length of a 3d line, then you can use the length3d 
function 
https://docs.qgis.org/3.22/en/docs/user_manual/expressions/functions_list.html#length3d

Best regards.

Andrea Giudiceandrea