Object re-center, how to?

[DaveS]

I am in need of adjusting the center of an object in AC3D, but am at a loss on how to do this. I have checked the manual and the only mention is the Re-centre option. To quote from the AC3D manual:

Re-centre

Object centres define the ‘local origin’ of AC3D objects. Object centres can be seen by switching on the '+' button on the main Orth menu. This function sets this origin at the centre of gravity. This can be useful for specifying where the pivot points or local-origin of an object are.

It seems to mention an "Orth" menu, but that seems to have morphed into the 2D menu, so this section might need updating. In fact, the "Orth" menu doesn't seem to have existed well over 14 years as I don't recall seeing since 2008 when I first started using AC3D.