Block

		The most basic 3D object is the Block.  AutoCAD requires a Length, Width, and Height to create a Block.  There are two ways to define the size of the Block in AutoCAD.  The first way to create a Block is with a starting coordinate and ending coordinate.  If your starting coordinates are (0,0,0), a second coordinate of (3,5,6) will create a Block 3 wide, 5 long, and 6 high.  This is how the Block to the right was created.  If you do not know the height of the Block initially, you can enter in a 2D coordinate (ie (3,5)) which will create a 3x5 base.  From there, you can enter the height, or click somewhere in model space to choose the height.  Using this method, the height of the Block will change up and down as you move the mouse around.
		The second way to create a Block is to enter the length, width, and height separately once you choose the starting point.  When AutoCAD prompts for the Other Corner, type "L" into the command bar to enter just the length of the Block.  After that, you will be prompted for the width and height of the Block.  This method is most helpful when two of the dimensions are already defined by an existing part of your drawing and you want to just use model space to select these dimensions.