CAD to XYZ points

I am trying to find a way of outputting a text file of coordinates of
points along the geometry of my CAD model. I have found a routine that
will extract a list of all the points along splines, and any other
points. What I want though is a way to produce a file of coordinates
representing points at a given spacing along all geometry.

ie if I have a 5 x 5 square drawn I want to be able to get a list of
20 points lying at the corners, and also at an interval of 1 along the
lines. Same for circles arcs etc.

I use 3D and 2d cad packages, so it would be nice to find a way to
create a "point cloud" over a 3D surface too.