Calculate curvature in the script process-surfaces-hemisphere

[zrk8635]

Hi
I was trying to run the dhcp-structural-pipeline, and I noticed the command in process-surfaces-hemisphere:
run mirtk calculate $outvtk/$hs.curvature.vtk -mul -1 -scalars Curvature -out $outvtk/$hs.curvature.vtk
Why was the curvature multiplied by -1 ?
If i want to calculate k1, k2, gaussian curvature and curvedness, do i need to multiple these indices by -1 ?

Thank you,
ruoke