Holes in 3d objects

You have to "Subtract" the hole from the object. The "Subtract" command is under "Modify"-"Solid Editing"
Hope this is the answer your looking for

To amplify a little, there are three ways to build '3D' object in AutoCAD. In the order they were included in the software:
- Build an object an edge at a time, jointing lines to make a 3D 'wireframe'. It doesn't behave like a solid. You can't put a hole in it.
- Take a 3D wireframe and add surfaces, primarily with 'revsurf' and 'tabsurf'. Again, the result does not behave like a solid, and you can't put a hole in it.
- Build a solid 3D model by extruding a closed polyline, or using a command like 'box'. You can make a hole in that, but the method may be counterintuitive. One way, assuming you want to put a hole in a box: Construct a circle, and extrude it to make a cylindrical solid. If you have located the circle and its UCS properly, and extruded it far enough in the right direction, it will go through the box. You can then 'subtract' the cylinder from the box, leaving a box with a hole in it. It helps to start thinking like a machinist, i.e., constructing a drill in order to make a hole, by subtracting the drill from the workpiece. If the drill is contained entirely within the solid, you can subtract it, but it will be hard to see.
I suggest that you 'setvar' 'delobj' '0' without the quotes. That prevents AutoCAD from destroying the primitives as it builds the solid. That makes it much easier to go back and try something over.
-Mike-

Thanks guys that has made things alot clearer. Shaun