[Andy]

There used to be a setting which switched off the recalculation of normals every time vertices were moved/sized. The _force version would bypass checking this setting and always do thr calculations.

This was done because the common PCs at the time were very slow and the normal calculations took a long time.

These days, the normals calculations are optimised and machines are generally much faster, and the settings is no longer available.

so, it's safe to use the non _force function all the time.

Andy