%ind_dtb%

dtb=distance to boundary, unit=meters

Y%ind_dtb% contains the distance to boundary of the point, if the distance to boundary was computed. The distance to boundary is computed only if necessary for performance reasons.
distance to boundary computed value in Y%ind_dtb%
yes absolute distance to boundary
no maximum distance (local smoothing length)
To evaluate for which points the distance to boundary was computed see Y%ind_dtb_status%, for the algorithm ORGANIZE_DistanceToBoundary_Version.