MENGGAMBAR BANGUN RUANGDrawing Polyhedral

MENGGAMBAR BANGUN RUANG

Beberapa istilah penting:1. Bidang gambar2. Bidang frontal3. Garis frontal4. Bidang ortogonal5. Garis ortogonal6. Perbandingan proyeksi

(perbandingan ortogonal)

7. Sudut surut (sudut menyisi)

30

Contoh 1Gambarlah kubus ABCD.EFGH dengan panjang rusuk 4 cm, bidang BCGF frontal dengan BC horisontal, sudut surut 60 dan perbandingan proyeksi 3 : 4!

B C

DA

F G

HE

604 cm

3 cm

BC = 4 cmAB = ¾ BC rasio 3:4 = 3 cm

Langkah-langkah:1. Gambar bid frontal BCGF

dgn BC horisontal 4 cm.2. Ukur 60 dgn pusat B utk

menentukan titik A.3. Hitung panjang AB dgn

rasio 3: 4 thd BC. (AB = ¾ BC = 3 cm)

4. Menentukan titik D.

EXAMPLE 2Given a cube PQRS.TUVW whose edge length is 4 cm. Draw the cube if PRVT is frontal face, PR is horizontal frontal line, oblique angle is 30 and orthogonal ratio is 1 : 2!

PT = 4 cmPR = 42 = 5,6 cmQS = ½ PR (ratio 1:2) = 22 = 2,8 cmOS = 2 = 1,4 cm

VT

Q

S

U

W

4 cm

30P RO

Steps:1. Draw frontal plane PRVT

that PR horizontal.2. Determine 30 at point

O in the middle of PR to find point S

3. Find QS in ratio 1:2 to PR. (OS = ½ OR = 2 = 1,4 cm)

4. Determine point Q.

GROUP ACTIVITY

30A C

GE

B

D

F

H

4 cm

O

AE = 4 cmAC = 42 = 5,6 cmBD = ½ AC (ratio 1:2) = 22 = 2,8 cmOD = 2 = 1,4 cm

150B D

HF

C

A

G

E

6 cm

O

BF = 6 cmBD = 62 = 8,4 cmAC = (ratio 2:3) = = 5,6 cm

BD32

24

60A E

C G

B F

D H

4 cmAE = 4 cmAC = 42 = 5,6 cmAB = ¾ AE ratio = 3:4 = 3 cm

A B

CD

E F

GH

135

4 cm

AB = 4 cmAD = ratio = 3:5 = 2,4 cm

AB53

Individual Assignment

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