736 AutoCAD and Its Applications—Basics Copyright Goodheart-Willcox Co., Inc. Figure 24-5C shows an example of specifying 4 for the X axis and 12 for the Y axis to create a 4″ × 12″ beam. Figure 24-6 shows another example of using a 2D unit block. Enter negative scale factors to create a mirror image of a block. NOTE NOTE For most applications, insert annotative blocks at a scale of 1 to apply the annotation scale correctly. Entering a scale other than 1 adjusts the scale of the block by multi- plying the scale value by the annotative scale factor. Rotating Blocks The rotation options in the Insertion Options area allow you to insert the block at a specifi c angle. Deselect the Rotation check box to enter a value in the Angle text box. The default angle of 0° inserts the block as defi ned using the Block Definition dialog box. Check the Rotation check box to receive a prompt for rotating the block during insertion. You cannot rotate a block defi ned using the Match block orientation to layout option in the Block Definition dialog box. PROFESSIONAL TIP P R OFESSIONAL TIP You can rotate a block based on the current UCS. Be sure the proper UCS is active, and then insert the block using a rotation angle of 0°. If you decide to change the UCS later, any inserted blocks retain their original angle. Figure 24-5. A—Real blocks, such as this car, are drawn at full scale and inserted using a scale factor of 1 for both the X and Y axes. B—A schematic block is inserted using the scale factor of the drawing for the X and Y axes. C—A 2D unit block is often inserted at different scales for the X and Y axes. x = 1 y = 1 x = 48 y = 48 B C A x = 4 y = 12 Figure 24-6. A comparison of different X and Y scale factors used for inserting a 2D unit block. This example shows a block of a plan view window symbol inserted into a 6″ wall. x=36 y=6 x=28 y=6 3′-0″ Window 2′-4″ Window Original 2D Unit Block Insertion base point 1″ 1″