LINES

So we are all set to start the actual CAD, Computer Aided Drafting today. Read thorough and we will draw our First Objects in AutoCAD today itself…! For this we have to open our Assignment3.dwg. Do it!

You can turn off the SNAP and GRID if they are on. We are going to draw 3 Rectangles with the help of Line command which is the First Command of the Draw menu, pull it down and click on Line or type ‘L’ at Command Prompt and press Enter. These rectangles will form our plot boundary for 3 no. of layouts viz. – Ground Floor Plan, First Floor Plan and Terrace Floor Plan. We will draw these 3 rectangles with 3 different methods known as the Coordinate Systems of drafting by AutoCAD.

1. Absolute Coordinate System – With this the geometry is drawn by providing the exact X, Y and Z (if applicable) values of each point that forms the geometry. Most accurate and most difficult method as it is extremely difficult if not impossible to calculate absolute coordinates of every point in the drawing. Best suitable for Survey drawings where you have the ready data in terms of X, Y and Z coordinate.

We will draw the First rectangle with this system. Follow the steps below; your inputs are in RED.

Command: LINE Specify first point: 10',10'
Specify next point or [Undo]: 43',10'
Specify next point or [Undo]: 43',60'
Specify next point or [Close/Undo]: 10',60'
Specify next point or [Close/Undo]: c

Note – ‘C’ will close the current segment with the starting point, in our case 10’, 10’, and could be used for any geometry that needs to be closed at the starting point from the current point.

2. Relative Coordinate System – By this the objects are formed by providing the input with reference to the previous points in the geometry in terms of the distance and angle from the previous point. This is comparatively easier as we don’t need to know the absolute position of the point but its relative position to its predecessor. It comprises the use of two symbols @ (at the rate which denotes the distance from the previous point) and less than (at an angle that specifies the angle at which the next segment is to be drawn I respect of the previous one)

We will draw the Second rectangle with this system. Follow the steps below; your inputs are in YELLOW.

Command: LINE Specify first point: _from Base point: click on point 43', 10' : @10'<0
Specify next point or [Undo]: @33'<0

Specify next point or [Undo]: @50'<90
Specify next point or [Close/Undo]: @33'<180
Specify next point or [Close/Undo]: c

3. Polar Coordinate System – This is the easiest and most popular system by virtue of its being flexible, fast and efficient. In this we will use the combination of Mouse and Keyboard for our inputs. Mouse will provide the Direction of the Vector to be drawn and Keyboard will provide the Dimension that will complete the Vector. With different combinations of Angle Settings, we will be able to draw in various desired directions.

We will draw the Third rectangle with this system. Follow the steps below; your inputs are in GREEN.

Command: LINE Specify first point: _from Base point: click on lower right corner point of second rectangle : @10'<0

Specify next point or [Undo]: Point the mouse in right direction and type 33'

Specify next point or [Undo]: Point the mouse in up direction and type 50'

Specify next point or [Close/Undo]: Point the mouse in left direction and type 33'

Specify next point or [Close/Undo]: c

Congratulations! We have just drawn THREE Rectangles with Line command within the Limits using all the Coordinate Systems and a Point Filter (remember _from Base point, that’s it!) Tomorrow we will see other commands of the Line group… Stay tuned…!