AutoCAD routine for calculating area's and centroids

For estimating sailarea's and centre of efforts I was wondering if anybody does have an autoCAD routine (lisp) for instance, that's capable of automatically calculate:

- the area's of different polylines/regions
- export this area's to a table
- place circle's or pre defined blocks at each centroid
- place a circle or block at the total centroid?

Or are there other smart way's to do this?

 

The autocad VBA acadregion class has both area and centroid properties so a VBA macro will be an easy option for you.