Practical Autodesk AutoCAD 2021 and AutoCAD LT 2021
上QQ阅读APP看书,第一时间看更新

The Object Snap override

Sometimes, it can be overwhelming to work with all these Object Snaps, and in drawings where there are lots of snap points close to each other, it can really get difficult to snap to any specific point. In those situations, you can use the Object Snap override to snap to the point that you need, overriding all other points even when they are active on the Object Snap menu.

To use the Object Snap override, select any draw command, preferably the Line commands, and then press and hold the Shift key until you see the override icon next to the cursor, as shown:

F igure 3.24: The Object Snap override icon next to the cursor

When you see the override icon, right-click on your mouse and you will get an Object Snap menu. Select the Object Snap point that you want to use for that command and then move your cursor close to the drawing. You will notice that now, AutoCAD will only snap to the selected Object Snap point and it will not highlight any other Object Snap, even though they are still active in the Object Snap menu.

One of the practical applications of this Object Snap override is in a situation as in the following figure. In the figure, we have two circles and we want to make a line that is at a tangent to both of the circles:

F igure 3.25: Two circles made with different radii 

Here, if you start with the Line command, then you need to start directly at the tangent point on the circumference of one of the circles, but you can't do that without actually making the line and when making the line, you need to specify a fixed point, which you can't do on the circumference of the circle.

In this situation, select the Line command then press and hold the Shift key and then right-click to get the Object Snap override menu. Select Tangent from this override menu and then click on the circumference of the bigger circle and now you will notice that you will end up with a line that follows the circumference of the circle in the tangent direction, just like the Nearest snap. Repeat the Object Snap override and then select Tangent again and this time click on the smaller circle and you will end up with a line that is at a tangent to both of the circles.

In this case, you can't use Nearest to snap to the first circle as the nearest snap will only let you snap to the circumference of the circle and it will not let you make the tangent line.

Using this method, you can make four tangent lines, as in the following figure, which otherwise is difficult, if not impossible, to do using direct Object Snaps:

     F igure 3.26: Four tangent lines made with the Object Snap override option between two circles

So, as you have noticed, the Object Snap override is a great way of suppressing all the Object Snaps except the selected one in the drawing. If you want to exclusively use an Object Snap, then instead of hiding all other Object Snaps from the Object Snap menu, use the Object Snap override and you will have the same result.

As you have noticed, Object Snap is an indispensable tool when it comes to creating a precise drawing. Just like Object Snap, there is another status bar option called Object Snap tracking, which makes the process of creating precise drawings easier. In the next section, we will learn about using Object Snap tracking, too.