How can I produce the sums of total points in "voxel pillars"?

[mavavilj]

How can I produce the sums of total points in "voxel pillars"?

Intuitively I started with voxel_metrics(las, ~length(Z),

But after this I'd need to sum along Z-axis on each X-Y "block".

And I haven't been able to figure out how to do this effectively.

(sorry if this forum isn't for these questions)

[Jean-Romain]

grid_metrics() ?

Your question is unclear. Please asked a clear and well defined question on gis.stackexchange with the tag lidr