Selction Preview

On complicated Autocad drawings selecting the correct element can be tricky, selections are much easier now that AutoCAD highlights (previews) objects as you mouse over them by either thickening the selection, showing it as a dashed line or both. However, it can still be difficult to select the right object when drawings become complicated with lots of overlapping objects. AutoCAD allows you to cycle through all overlapping objects under the cursor.

Method;
Hold down the Shift key and then repeatedly hit the Spacebar (Shift + Space). Each object under the cursor will be highlighted in turn and you can easily pick the one you want.

The same process can be used select sub-objects such as faces and edges on 3D Solids. To cycle through sub-objects, hold down the Control key and hit the Spacebar repeatedly (Ctrl + Space).