Getting Started with AutoCAD

Object Snaps

Suppose you want to draw a line from the center of the circle to the middle of the vertical line you extended earlier. AutoCAD has a feature that makes this very easy. These are the Object Snaps (or Osnaps "Oh-Snaps"). Type OS <ENTER> . You will see this dialog box appear.

You may also see a toolbar with these Osnaps as shown below.

ICON SETTING ICON SETTING Endpoint Perpendicular Midpoint Tangent Center Nearest Node Apparent Intersection Quadrant Parallel Intersection None Extension Osnap Setting Insertion Point Temporary Tracking Point   Snap From

You may select whichever points you want to 'snap' on an object. Here is a list of your options. Followed by the command entry to invoke the needed Osnap.

Endpoint - snaps to either the beginning or the end of an object such as a line - END Midpoint - snaps to the exact middle of a line or an arc - MID Center - snaps to the center-point of a circle or arc - CEN Node - snaps to 'nodes' (not covered in this course) - NOD Quadrant - snaps to any of the four quadrants of a circle - QUA Intersection - snaps to the point where two object cross - INT Extension - Snaps to the phantom extension of an arc or line - EXT Insertion - snaps to the insertion point of an object (such as a block or text) - INS Perpendicular - will snap so that the result is perpendicular to line selected - PER Tangent - snaps to create a line tangent to a circle or arc - TAN Nearest - will find the closest point an object and snap to that point - NEA Parallel -Snaps parallel to a specified line - PAR None - temporarily turns off all Osnaps. (Pressing your F3 Key is quicker) - NON Osnap settings - opens the Osnap dialog box. Temporary Tracking - Creates a temporary tracking point (see Object Tracking). From - Allows you to select a point, then denote a new location 'from' that point using relative co-ordinates. This can save you the time of drawing (and erasing) construction lines.

Note: Beside each checkbox is a symbol. That symbol will show up on the screen when you have found a valid snap point. (An endpoint will show a small square). If you select the "Options" button, you can change the aperture size and the color of the Osnaps. Depending upon the background you are drawing on, this may be needed.

a. Check off the boxes as shown in the dialog box above (Object Snaps On, Endpoint, Midpoint, Center) and press OK. b. Begin the LINE command. Move your cursor around the screen and you'll see that as you get close to an object, it will 'snap' to one of the points that you had checked off in the dialog box. Place your cursor on the circle (not the middle of the circle) until you see a small purple circle appear at its center. Left-click to make this the start point of the line. Move the cursor towards the middle of the vertical line until you see a small triangle appear. (Remember this is the symbol for 'midpoint'). When you see it left-click to accept this as your endpoint. Press <ENTER> to end the line command. c. Save your drawing. d. Print your drawing

TIP: Before you select the Osnap you want, you can press the TAB key on your keyboard to cycle through the available Osnaps in the area of your cursor.