Leonid Nemirovsky also discusses Measuregeom, a tool that allows you to take volume and other measurements of your line work or object.
"Type Measuregeom at the Command prompt and a very handy measuring tool is at your disposal. Select the type of data you want to find, and follow the onscreen instructions. You can gather important information from your drawing such as distance, angle, radius, area, and volume."
NOTES FROM CADALYST TIP PATROL: The volume function will ask you to select points to establish a perimeter. Then it will ask you to enter the depth of the shape. This means that you don't need to create a 3D model to find the volume of an object, just its outline. The other measurements work in a similar manner. If you are trying to find an area or volume, the command will not allow you create a self-intersecting area. The Area command will also give you the perimeter of your shape.