Dasar Menggambar Bentuk (lanjutan )

By:

Dr. Eng. Rudi W. Prastianto

Dasar-dasar Menggambar Bentuk

1. Menggambar Garis Singgung

2. Menggambar Elips (Pendekatan):

a) Dengan metode 2 Lingkaran Konsentris.

b) Dengan metode Oblong.

Tentukan titik A pada lingkaran sehingga PA = OP = jejari lingkaran.

Buatlah garis OA dan diperpanjang hingga B dengan AB = OA.

Buat garis PB Didapatkan garis singgung PB melalui titik P pada lingkaran.

1. Menggambar Garis Singgung

Apakah Garis Singgung itu ?

1. Menggambar Garis Singgung

2. Menggambar Elips (Metode Dua Lingkaran Konsentris)

a. Metode 2 Lingkaran Konsentris

1. Draw the major and minor axes AB and CD and locate the centre O.

2. With centre O and major axis and minor axes as diameters, draw two concentric circles.

3. Divide both the circles into equal number of parts, say 12 and draw the radial lines.

4. Considering the radial line 0-1-1, draw a horizontal line from 1' to meet the vertical line from 1 at P1.

5. Repeat the step 4 and obtain other points P2, P3, etc. 6. Join the points by a smooth curve forming the required

ellipse.

2. Menggambar Elips (Metode Oblong)

b. Metode Oblong

1. Draw the major and minor axes AB and CD and locate the centre O.

2. Draw the rectangle KLMN passing through A,D,B,C.

3. Divide AO and AN into same number of equal parts, say 4.

4. Join C with the points 1', 2', 3' .

5. Join D with the points 1, 2, 3 and extend till they meet the lines C1', C2', C3', respectively at P1, P2 and P3.

6. Repeat steps 3 to 5 to obtain the points in the remaining three quadrants.

7. Join the points by a smooth curve forming the required ellipse.