update: works now in AutoCAD 2002
Quickmesh3D.lsp provides you an easy way to create meshes or 3dsolids and make holes to those. Forget thicknesses, extrusions, boxes and wedges and start to use Quickmesh3D.lsp
It has been my long-time attempt to write a lisp that could create a 3D-object by a specified set of points in 3D-space! Here's the result! Could it be easier?
You may also extract the information from other objects, like for instance contour lines in a landscape model.