How d'you increase the mass of a vertex?

[McHale 0]

n/t

[maddogx 13]

In the Geometry LOD, you select the vertices you want to increase the mass of, then (if you don't see the mass window) click 'Window' up in the menu bar and then click 'Mass'. Now a window should be there, in which you can set the mass of the selected vertices.