這個真是個難題，現在我把下載的一個做法提供給大家，供參考
: r" y# b/ a# h+ P* ^1.先用直線命令畫一直線（圖1）。過程如下：
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命令: LINE' F+ G/ E3 m$ I& `: g3 u
指定第一點: 0,0
$ ?) _$ I! [( q* D 指定下一點或 [放棄(U)]: 'cal
$ f. Q4 Z. h; Y( d# ?( _/ q >> 表達式: +[100*100/200<-30]
% ?5 X; @8 Y9 t9 C# M (43.3013 -25.0 0.0)
# o+ |6 O- K0 E0 S 指定下一點或 [放棄(U)]: ↙) ]) ?7 x% B6 |$ r; f6 s
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2.移動該直線，如圖2。
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4 T9 g- u% C( u' j 3.用多段線命令畫多段線，先向-60度方向拉出適當長度，如圖3。3 P: R( a' k1 S* x$ k2 B+ h( `
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4.繼續畫多段線，完成一個直角三角形，如圖4。! A- m7 x9 Z( z& N8 H* U
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- I; v6 P& F4 r 5.用REVOLVE命令旋轉直角三角形，生成一個三維實體，如圖5。過程如下：7 s! v f. i3 I- ~. B. D
# ~/ I# n: Q, _" I% t! _ 命令: REVOLVE: Y$ Y6 B- E( R' X
當前線框密度: ISOLINES=4: G1 k% W Q% W6 c' H* H
選擇對象:（選擇直角三角形）5 w. e4 v% o: [1 |" T8 [; q1 C
選擇對象: ↙
" l8 D) {! j. H' r5 G' k+ { 指定旋轉軸的起點或- Q$ H, G, @5 k) [7 s- m0 ~
定義軸依照 [對象(O)/X 軸(X)/Y 軸(Y)]:（捕捉A點）0 P, f1 ~0 y2 ~# @- N- j& e2 l3 R
指定軸端點: （捕捉B點）7 Y3 H5 l" }! Z4 {7 h) x! [2 W+ T& w: B
指定旋轉角度 <360>:↙
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0 u3 @, O9 N% U2 F# Q 6.用SECTION命令切割三維實體，生成一個面域，如圖6。過程如下：
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命令: SECTION5 ~! R, j+ e; z7 u" F' [- U8 k. e
選擇對象: (選擇上一步生成的旋轉實體)
0 K8 }3 J+ K2 b 選擇對象: ↙- B( i- N1 N1 w" b
指定截面上的第一個點，依照 [對象(O)/Z 軸(Z)/視圖(V)/XY 平面(XY)/YZ 平面(YZ)/ZX 平面(ZX)/三點(3)] <三點>: yz! H( `2 [. z2 A# ?5 o0 S/ s6 X
指定 YZ 平面上的點 <0,0,0>:（捕捉C點）* n" m* C& F" J0 u! d# s4 U9 k
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# l9 H- u' J! p; M9 M2 k 7.用rotate3d命令對上一步生成的面域進行三維旋轉，如圖7。過程如下：
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命令: rotate3d" |: u! A4 C. Z+ m0 D2 U- I* L: q
當前正向角度: ANGDIR=逆時針 ANGBASE=0
. ~2 S" n& u! Q( s 選擇對象: （選擇上一步生成的面域）" q) Y4 l) u+ w7 a1 N
選擇對象: ↙% S1 j9 p9 z+ Z$ m( x
指定軸上的第一個點或定義軸依據[對象(O)/最近的(L)/視圖(V)/X 軸(X)/Y 軸(Y)/Z 軸(Z)/兩點(2)]: (捕捉C點) 指定軸上的第二點:（捕捉D點）
8 U6 D3 {# u+ o( d" v 指定旋轉角度或 [參照(R)]: 90
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8.先用EXPLODE命令分解旋轉后的面域，再清理圖面，刪除不需要的圖元，如圖8。& f- a5 G1 A4 R; R5 H$ x$ ], F3 w
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9.移動拋物線，如圖9。完畢！
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: J2 [0 L8 g3 J7 y: \- `Sub trparabola() 1 z( L4 H" I/ q$ i' u( L% N
Dim bq1, bq2, pt1, pt2 As Variant ; q% u0 \$ p7 S0 M
Dim aa, ll, yy, a1, a2, a3, a4, aa1, pt3(0 To 2), bq4(0 To 2) As Double 7 E( P+ L3 u0 Q, A5 [! v' G8 D
Dim bq3(0 To 2) As Double
/ d% M1 P0 }- Y/ J9 pDim ae As Double : h# j+ R* e5 M7 L2 K, O3 t
Dim pt33(0 To 2) As Double
% Z9 t# q/ G9 d) k0 p& cDim ptarr(0 To 7) As Double ( D4 _3 R* w1 }/ H
Dim alt As Variant $ c8 [0 a, A* K
Dim objboltb As Acad3DSolid
- S6 s" S5 v; b0 lDim al As Variant 9 I" C1 c! w g7 t8 u H
Dim lens As AcadLWPolyline 7 T5 z! y8 H3 |+ u. [: ~' |
* ] x2 q$ W' c/ a2 g1 c2 f7 A'求個控制點
3 r7 V# }2 W7 n! Rbq1 = ThisDrawing.Utility.GetPoint(, "拋物線頂點: ")
8 `# j" w, Z1 s; a1 }; w" xaa = ThisDrawing.Utility.GetReal("輸入二次項系數： ")
' D ~6 w) M+ n7 ~) \ll = ThisDrawing.Utility.GetDistance(, "輸入開口弦長： ")
0 l/ V* Y7 ?- G, R0 a3 ~aa1 = 1 / aa
6 c3 E4 ]( T e' x& nyy = aa * (ll / 2) ^ 2
6 t3 @: @0 H+ V' s8 ka1 = ThisDrawing.Utility.AngleToReal(-30, acDegrees)
7 k7 Y8 h7 I) [& P, G8 ]a2 = ThisDrawing.Utility.AngleToReal(30, acDegrees)
& [) j) F: E3 Q& \2 va3 = ThisDrawing.Utility.AngleToReal(90, acDegrees) p2 q" O7 B' @' `6 a) ~9 c! m& ~
a4 = ThisDrawing.Utility.AngleToReal(150, acDegrees) 4 v' M0 I) l& z$ _$ o
bq2 = ThisDrawing.Utility.PolarPoint(bq1, a2, yy)
+ Y2 Q8 M0 ]) a: z1 v6 {pt1 = ThisDrawing.Utility.PolarPoint(bq1, a4, aa1) # Q. s. ^! A5 J2 ~% v3 X$ _
pt2 = ThisDrawing.Utility.PolarPoint(bq2, a3, aa1) # _6 T/ n9 ^$ Z4 D9 E1 G) C3 k
pt3(0) = pt2(0): pt3(1) = pt1(1): pt3(2) = pt1(2)
" a' p( q! c& Q( |, @bq3(0) = bq2(0): bq3(1) = bq2(1): bq3(2) = bq2(2) + 10 B9 ~" {6 H9 A6 {$ p5 z
bq4(0) = bq2(0): bq4(1) = bq1(1): bq4(2) = bq1(2) 2 U, m# n; m9 D; A/ t4 J2 D4 R
pt33(0) = 10: pt33(1) = 0: pt33(2) = 0 3 u7 K8 q/ }7 _! F* e2 T* d
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ptarr(0) = pt1(0) 0 e1 ^" l9 _- f3 B. G
ptarr(1) = pt1(1)
6 t, v/ t6 O, n$ H1 w, K5 rptarr(2) = pt2(0)
3 [' u/ o8 C& S4 I1 P' R9 J# Wptarr(3) = pt2(1) 6 e/ L+ _4 z8 P V
ptarr(4) = pt3(0)
* q# ~! m5 e( |7 J- mptarr(5) = pt3(1) - E3 }- e, M$ m3 R/ R
ptarr(6) = pt1(0) 3 P( A* z: O0 n7 z8 C4 N
ptarr(7) = pt1(1) 0 z F/ x8 r+ V- G! R
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Set lens = ThisDrawing.ModelSpace.AddLightWeightPolyline(ptarr) ) D5 S' X9 Y, D" [- _) s
Dim objlist(0) As AcadEntity 3 y1 v" x2 a8 a6 |
Set objlist(0) = lens 4 Q8 h- e2 I$ @. B6 _
n* F, |$ @" w'將多段線變為面域
+ O7 i: n! X# _. \2 l4 @Dim altregion As AcadRegion
7 l) v0 ]7 W7 f- w& Dalt = ThisDrawing.ModelSpace.AddRegion(objlist)
# F7 O4 A3 ]" Z# E, \ ]6 jobjlist(0).Delete
" x# y1 s: J; ]3 PSet altregion = alt(0)
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'旋轉面域得到圓錐
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5 S+ J' j% N7 l% j$ e8 d- c: CSet objboltb = ThisDrawing.ModelSpace.AddRevolvedSolid(altregion, pt1, pt33, ae) * n/ {0 m* R# u0 H7 u7 ^
altregion.Delete
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: N! e# I2 n2 Z4 \2 K! y' ^'切圓錐得到拋物線 & L2 o0 k% n, `, o0 @: ?
Set al = objboltb.SectionSolid(bq1, bq2, bq3)
! ]1 `/ R0 A3 `6 |% |. kobjboltb.Delete # F2 L, A8 C: H/ b( A
al.Rotate bq1, a1 1 h* l' b% G: N Z
al.Rotate3D bq1, bq4, a3
! o0 m) j ]2 D# H, vDim explodedobjects As Variant 7 n$ _. s# L+ V' s! C1 f+ a9 q. f
explodedobjects = al.Explode / z: r! k5 q# F2 U/ l* K' |" M+ X; f
al.Delete b, N6 X& }6 T& x) J
Dim i As Integer 8 ~% K$ `7 b# u3 x
Dim kind As String
& Q( J$ O" r6 {7 r* v8 a* q) JDim parabolaobject As AcadSpline . U |9 ^2 e# n, J2 ]
For i = 0 To UBound(explodedobjects) 6 P7 F% K. W4 R" H% h8 X3 l& `
kind = explodedobjects(i).ObjectName 9 R/ v l6 j2 t4 [6 m9 t6 u
If kind = "AcDbLine" Then 4 L! L! P2 Z7 E; r$ r L& v# }0 Q
explodedobjects(i).Delete
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Set parabolaobject = explodedobjects(i) $ L1 H4 q$ v- }( K1 N
End If
) [7 V- V) U: e8 QNext
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" ^ g2 q# j& L8 `- u5 J/ p; I'旋轉拋物線 ! o. x( H- c0 }9 o, t! ~
ThisDrawing.SendCommand "rotate" & vbCr & "(Handent """ & parabolaobject.Handle & """)" & vbCr & "" & vbCr & bq1(0) & "," & bq1(1) & vbCr & n4 s4 N7 o& g& q2 F
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End Sub5 Q# L3 ~& v# |+ U
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樓主: hyj_9766
發表于 2009-3-29 19:47:49
要活到老學到老,所以我們年輕人更應該抓緊學習了，
