这个真是个难题，现在我把下载的一个做法提供给大家，供参考
' F }# {- Q2 O: w& _1.先用直线命令画一直线（图1）。过程如下：
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3 e T& V/ m' Z7 J1 W 命令: LINE/ O5 o4 C5 R0 b I
指定第一点: 0,0* Y( f% ^: w- ~$ ~( i1 \
指定下一点或 [放弃(U)]: 'cal
: n/ \9 \5 Q" f4 n9 T- w' Z >> 表达式: +[100*100/200<-30]: h6 Q' p Y7 X. W+ D; [2 U* {
(43.3013 -25.0 0.0)
. }% G3 `) L( I: Z' l 指定下一点或 [放弃(U)]: ↙2 Q4 Z) U" b9 _) ^3 e5 A
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$ ?' l c9 |6 e6 t4 I! I 2.移动该直线，如图2。. _% F/ D! e; N7 r$ R8 `
& |. Z( _$ @8 n- M! W7 z 3.用多段线命令画多段线，先向-60度方向拉出适当长度，如图3。: w3 A a/ ?$ x) ?! u9 L ~$ [
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6 @2 g) [% k% r; L/ } 4.继续画多段线，完成一个直角三角形，如图4。
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* S* b9 Q5 _1 v) N# T 5.用REVOLVE命令旋转直角三角形，生成一个三维实体，如图5。过程如下：* q% a# i! K1 _+ T5 [2 I4 D
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命令: REVOLVE
% K- f: T$ l/ j+ f 当前线框密度: ISOLINES=4
& P6 \& C- L5 q% l" A" B 选择对象:（选择直角三角形）% V R: q# z! v
选择对象: ↙
. D6 |: r: Q! J9 M. r% g- t+ s 指定旋转轴的起点或
- W8 I- P' q* _7 |/ [" h 定义轴依照 [对象(O)/X 轴(X)/Y 轴(Y)]:（捕捉A点）
# A8 U, ?" D! C7 `' l6 d 指定轴端点: （捕捉B点）) w- g0 {1 T: `! b( g, i
指定旋转角度 <360>:↙, R6 K, U8 U9 Q! q4 j! Z
7 X+ _1 L. t9 `& @( {- K: m 6.用SECTION命令切割三维实体，生成一个面域，如图6。过程如下：) }" T1 d$ v6 ]) X
4 x! h' S3 x( [4 I9 t, H- n/ \ 命令: SECTION$ Q Z2 ^, N, W
选择对象: (选择上一步生成的旋转实体)
- k0 ^9 v) m; [% i1 u 选择对象: ↙
9 ~/ r6 W0 d+ J+ _ 指定截面上的第一个点，依照 [对象(O)/Z 轴(Z)/视图(V)/XY 平面(XY)/YZ 平面(YZ)/ZX 平面(ZX)/三点(3)] <三点>: yz
2 I0 I4 F4 D# O; R! G& b$ v 指定 YZ 平面上的点 <0,0,0>:（捕捉C点）( `, `* \+ u+ v% g/ ]
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7.用rotate3d命令对上一步生成的面域进行三维旋转，如图7。过程如下：
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命令: rotate3d6 E2 [7 V" m6 c$ o, T
当前正向角度: ANGDIR=逆时针 ANGBASE=0
' U- O4 R+ o4 t& L0 ]- h 选择对象: （选择上一步生成的面域）
- G0 ]4 P# ^6 T+ I 选择对象: ↙
2 g _' ^+ i) n& x. ^ S. l1 z 指定轴上的第一个点或定义轴依据[对象(O)/最近的(L)/视图(V)/X 轴(X)/Y 轴(Y)/Z 轴(Z)/两点(2)]: (捕捉C点) 指定轴上的第二点:（捕捉D点）3 V, t7 \4 i! c( Q
指定旋转角度或 [参照(R)]: 90
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8.先用EXPLODE命令分解旋转后的面域，再清理图面，删除不需要的图元，如图8。0 }$ F# F3 b# L% o* `; j
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9.移动抛物线，如图9。完毕！5 u( q: j9 F" I: J( f
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http://bbs.icax.cn/register.php, g! y/ @0 W: I, F2 H
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Sub trparabola() 3 L! `2 Z! a, Z0 N# E7 D
Dim bq1, bq2, pt1, pt2 As Variant
) v- m& e5 r3 I | z- `& j" mDim aa, ll, yy, a1, a2, a3, a4, aa1, pt3(0 To 2), bq4(0 To 2) As Double
) ~+ P/ s- ^0 Y4 ZDim bq3(0 To 2) As Double
9 e+ d! d, m# i* M9 R. Z) BDim ae As Double
" b: p# j+ [0 S7 wDim pt33(0 To 2) As Double
+ S, D: f2 _7 X; I4 cDim ptarr(0 To 7) As Double
; _9 f$ x! x, M- L, E" t) B4 PDim alt As Variant
# w) J: F9 I3 RDim objboltb As Acad3DSolid ! m' V5 i; u" g% p
Dim al As Variant $ ?3 R$ v% u# n5 B0 o
Dim lens As AcadLWPolyline
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; f5 ?$ v2 k! D g% O S8 y'求个控制点
; U% i8 \2 f: h. I( k! Lbq1 = ThisDrawing.Utility.GetPoint(, "抛物线顶点: ") , W: N: L. W7 {& t3 W+ i
aa = ThisDrawing.Utility.GetReal("输入二次项系数： ") ' m4 h2 x1 l1 `5 h( ]
ll = ThisDrawing.Utility.GetDistance(, "输入开口弦长： ")
- y% n4 v+ ^+ \: zaa1 = 1 / aa ; f: F8 L' `0 |& e
yy = aa * (ll / 2) ^ 2
( H' S: r% `% |a1 = ThisDrawing.Utility.AngleToReal(-30, acDegrees)
8 H8 L, C" p: ?8 ~a2 = ThisDrawing.Utility.AngleToReal(30, acDegrees) 3 b8 \% \' p. [% j8 R8 x
a3 = ThisDrawing.Utility.AngleToReal(90, acDegrees)
! {' D) Y' v) j1 O; Y) ^a4 = ThisDrawing.Utility.AngleToReal(150, acDegrees) 4 _' A1 @0 D% k) }! d; c: C
bq2 = ThisDrawing.Utility.PolarPoint(bq1, a2, yy)
4 {4 X* o3 h; A0 t0 z* P! t9 b/ y( C2 Zpt1 = ThisDrawing.Utility.PolarPoint(bq1, a4, aa1)
% A) G4 C+ p' _5 J4 Upt2 = ThisDrawing.Utility.PolarPoint(bq2, a3, aa1) Y+ }. ^3 h8 t8 Z
pt3(0) = pt2(0): pt3(1) = pt1(1): pt3(2) = pt1(2)
4 j/ L9 _8 P1 l' }; j( a2 fbq3(0) = bq2(0): bq3(1) = bq2(1): bq3(2) = bq2(2) + 10 ) e8 R& F( e% H! l- }( F h6 }) E
bq4(0) = bq2(0): bq4(1) = bq1(1): bq4(2) = bq1(2)
$ h1 @' L, h2 Ypt33(0) = 10: pt33(1) = 0: pt33(2) = 0 * T$ w3 d1 y0 o }. M5 H0 M$ e w4 K
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ptarr(0) = pt1(0) 3 Z. g _9 @- O
ptarr(1) = pt1(1)
# i% U; ~9 l; s6 o8 mptarr(2) = pt2(0) ) [5 ^8 Y" i# U
ptarr(3) = pt2(1)
7 j8 w2 i" E1 O* nptarr(4) = pt3(0) $ t) I4 [7 c# H- _. O' M/ d) a
ptarr(5) = pt3(1)
* G; K: ` S, S5 Iptarr(6) = pt1(0)
& Q, t0 J8 U- B- b( U5 w" B- J2 h2 _ptarr(7) = pt1(1) ' M1 S; M. {: t! |* i
5 ~3 x! R# n' d3 N'画多段线
" }5 M1 X& F9 j, D& B% p% u/ [0 ZSet lens = ThisDrawing.ModelSpace.AddLightWeightPolyline(ptarr) 6 q+ x+ M! S; B
Dim objlist(0) As AcadEntity
* r2 b* F& x5 P, B t. ASet objlist(0) = lens
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'将多段线变为面域 9 S* `. {( S; Z0 O6 [8 z
Dim altregion As AcadRegion 0 Z. q3 x5 n5 v+ ]* z8 p0 V. |- @( `
alt = ThisDrawing.ModelSpace.AddRegion(objlist) X# h# S0 `' M+ U! J4 i% h* g
objlist(0).Delete 1 g$ X; O* \' x" n' ]. g
Set altregion = alt(0)
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( q, G: v! P5 k h'旋转面域得到圆锥 0 X+ L, e7 Q+ D7 \# ~0 H4 e- v- ?. z
ae = 2 * Atn(1) * 4 & ]; J! e9 e# O, ~
Set objboltb = ThisDrawing.ModelSpace.AddRevolvedSolid(altregion, pt1, pt33, ae) ( N$ G. I% r4 q2 M! Q, @6 ]
altregion.Delete 7 Q1 `$ n/ {1 o% c
" A6 c1 ~( p" V! {! T4 |# V'切圆锥得到抛物线 + B8 P, U3 k: `
Set al = objboltb.SectionSolid(bq1, bq2, bq3) " n& h" c0 U" d3 W9 D* R
objboltb.Delete
! X& R0 z! ~: f. g6 i8 gal.Rotate bq1, a1
s9 w3 R- u- U zal.Rotate3D bq1, bq4, a3
" `- e2 x( v8 g9 @: ODim explodedobjects As Variant ; r( O6 ` G& |8 R
explodedobjects = al.Explode # g: u4 b! p0 t6 `' U0 w
al.Delete . t8 ~4 s3 D( B
Dim i As Integer
( K% W# {$ R! a5 p/ R& z' YDim kind As String
; O8 q( ?8 {3 h! hDim parabolaobject As AcadSpline * j9 T3 Z l( q9 C, E' K
For i = 0 To UBound(explodedobjects) 0 k" h! V _# k! Z
kind = explodedobjects(i).ObjectName
' h* h* @) v, P- AIf kind = "AcDbLine" Then l' Q/ g- V. h+ e/ J. c
explodedobjects(i).Delete
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Set parabolaobject = explodedobjects(i) 4 ~- k" A! q+ R. j4 \5 w
End If
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'旋转抛物线
! n7 t) m0 e K+ s+ v0 yThisDrawing.SendCommand "rotate" & vbCr & "(Handent """ & parabolaobject.Handle & """)" & vbCr & "" & vbCr & bq1(0) & "," & bq1(1) & vbCr
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End Sub, E& A) D1 z% @+ _" i6 \6 z& d
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楼主: hyj_9766
发表于 2009-3-29 19:47:49
要活到老学到老,所以我们年轻人更应该抓紧学习了，
