Bi ging V k thut
1. Mi quan h gia cc hnh chiu
Cho thc ca im A nh hnh v:
Nhn xt: – Hnh chiu ng A1 c xc nh bi OAx v z OAz A A A – Hnh chiu bng A2 c xc nh bi OAx v OAy x A O A – Hnh chiu cnh A3 c xc nh bi OAy v OAz1 z x
A2
Ay
Bi ging V k y thut
i vi cc hnh chiu ca im:
+ Hnh chiu ng v hnh chiu bng c chung kch thc song song vi trc Ox ( xa cnh) + Hnh chiu bng v hnh chiu cnh c chung kch thc song song vi trc Oy ( xa) + Hnh chiu cnh v hnh chiu ng c chung kch thc song song vi trc Oz ( cao)z A1 x Ax Az A3 y
Ay
A2
Ay y
Bi ging V k thut
i vi cc hnh chiu ca vt th:
– Hnh chiu ng v hnh chiu bng ca vt th c lin h ging ng, do c chung kch thc ngang (kch thc di) – Hnh chiu ng v hnh chiu cnh ca vt th c lin h ging ngang, do c chung kch thc cao – Hnh chiu bng v hnh chiu cnh ca vt th c chung kch thc su (kch thc rng)Bi ging V k thut
Bi ging V k thut
Bi ging V k thut
Bi ging V k thut
2. c bn v
c bn v l nghin cu cc hnh biu din cho hiu c hnh dng, kt cu ca vt th.
Trnh t c bn v: – Xc nh hng chiu cho tng hnh chiu, theo cc hng t trc, t trn hnh dung ra mt trc, mt trn ca vt th. – Phn tch ngha cc ng nt trn tng hnh chiu, mi quan h gia cc ng nt trn cc hnh chiu. – Tng hp nhng iu phn tch trn hnh dung ra hnh dng ca vt th cn biu din.Bi ging V k thut
3. Cc v dV hnh chiu cnh ca vt th cho nh hnh v Trnh t thc hin: – c bn v – V hnh chiu cnh v hnh chiu th 3 ca mt vt th c d dng, thng phn tch vt th thnh cc b phn n gin hn. V hnh chiu th 3 ca tng b phn v tp hp li c hnh chiu th 3 ca ton b vt th. Nguyn tc chung l v phn thy trc phn khut sau, b phn ch yu trc b phn th yu sauBi ging V k thut
Biu din giao tuyn cc b mt trn vt th (T.77-81 GT) Giao 2 mt tr
Cho 3 hnh chiu thng gc v cha y ca mt s vt th. Hy v b sung cc nt v cn thiu trn cc hnh chiu .
Cho 2 hnh chiu thng gc ca mt s vt th. V hnh chiu th 3 ca chng theo hai hnh chiu cho
Bi tp 1: V hnh chiu th 3 t 2 hnh chiu cho 54
15
13
26
90
54
54
26 15
3 0
54
54
14
3 0
54
13
7 54
54 30
42 54
26
7 13 15 54 14
Bi tp 2: V hnh chiu th 3 t 2 hnh chiu cho
13
28
15 120
64
42
50
13
28
3 6
15 120
64
42
50
13
R1
28
3 6
15 120
64
42
Bi tp 3: V hnh chiu th 3 t 2 hnh chiu cho
18
R7
22 48 36 14
50
22 48
18
14
30
18
R7
22 48 36 14
50
22 48
18
14
30
50 18 12
R714 48 36 36 22 22 22 48
18 14
30
50
18 9 30