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8 U9 w+ A. [1 y Z9 M
1.先用直线命令画一直线(图1)。过程如下:
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8 y/ J8 G' V* I$ J, X/ i- i! ]7 H9 v3 \ 命令: LINE
5 C' q8 l. h% w$ N3 b5 ]- L 指定第一点: 0,06 n r6 R! A$ o* u( r9 T
指定下一点或 [放弃(U)]: 'cal
( a* \0 ?4 @, O) @( Q8 X: n8 | >> 表达式: +[100*100/200<-30]
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指定下一点或 [放弃(U)]: ↙
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2.移动该直线,如图2。
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$ X; y7 r- k9 o: W9 p: ` 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。9 @) b& J9 i, T0 k3 L
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4.继续画多段线,完成一个直角三角形,如图4。5 w6 F3 E/ M6 ~6 V/ }$ h+ R
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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:
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命令: REVOLVE2 p& x% ^2 L* C1 `- E3 E( C* q6 ?
当前线框密度: ISOLINES=4 W; S- @3 x# k8 B) Y# a4 M& b2 Q
选择对象:(选择直角三角形)
1 K7 T' Z- w- V 选择对象: ↙
, o; I; Q: y# ] b4 {/ t 指定旋转轴的起点或" ~( `" M* ^1 D0 p0 H. a3 t4 }% d
定义轴依照 [对象(O)/X 轴(X)/Y 轴(Y)]:(捕捉A点)
8 E% D" V$ R) I, R5 ^& H 指定轴端点: (捕捉B点). }, k; c6 {+ }7 H8 a. T
指定旋转角度 <360>:↙' O6 A$ o$ H9 H1 {7 g
3 u* \3 [: G# F2 a7 n8 I* i8 B( @9 ^ 6.用SECTION命令切割三维实体,生成一个面域,如图6。过程如下:; C6 m/ w& f; m$ g/ E
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命令: SECTION5 @: S3 N2 ~6 A+ @! L+ {# u
选择对象: (选择上一步生成的旋转实体)
- Z1 a# |* T/ P+ o( d5 N4 h" Q 选择对象: ↙
. {1 E: ?# X. U' Y( i# p 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* V) \$ a3 \) s( N( v! D+ G
指定 YZ 平面上的点 <0,0,0>:(捕捉C点); L% ~0 y$ ?6 G# A2 R; ?: v. _- D
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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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+ e& p0 |9 p @" } 命令: rotate3d
2 I+ L" t3 f4 s6 I/ s 当前正向角度: ANGDIR=逆时针 ANGBASE=0
5 E5 f4 ]2 b% y ? 选择对象: (选择上一步生成的面域)& q( C" y K/ V' H( b. r- z4 Y3 c
选择对象: ↙* n8 h+ [. }- w! h6 b+ M) ]
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)
" T1 B; J& |5 Q/ {7 L 指定旋转角度或 [参照(R)]: 90
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. X. }- b4 {7 D9 [1 R) g* O1 D 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。- `! }/ ^# K4 a6 \! X1 D
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' e, I$ X: V7 Y/ i3 J8 N. W 9.移动抛物线,如图9。完毕!
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& S( o, Y2 K' r% F# d! XSub trparabola()
* {- i% u5 s5 M( ^6 O4 s( m9 ZDim bq1, bq2, pt1, pt2 As Variant ' q" w7 t- Z' f$ O
Dim aa, ll, yy, a1, a2, a3, a4, aa1, pt3(0 To 2), bq4(0 To 2) As Double
6 r! M- c/ K g+ e$ MDim bq3(0 To 2) As Double
: V( h0 r/ T4 j. H$ jDim ae As Double
, |' } P/ e8 s$ tDim pt33(0 To 2) As Double 4 d" u6 M0 g+ s1 Z% J' o! M
Dim ptarr(0 To 7) As Double
' G! l: ^& c) A* LDim alt As Variant " _2 l9 T1 k( t
Dim objboltb As Acad3DSolid
8 g: u' J0 p2 N# U* M6 j jDim al As Variant # C: E+ {3 q+ r& v' d; f
Dim lens As AcadLWPolyline 5 r+ @3 o6 e3 n' |, f- O% o
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'求个控制点
6 `* l+ H0 m" l h# c0 e ebq1 = ThisDrawing.Utility.GetPoint(, "抛物线顶点: ") 5 K/ p# p& Y( V0 l
aa = ThisDrawing.Utility.GetReal("输入二次项系数: ") % E; t; U6 k [6 c
ll = ThisDrawing.Utility.GetDistance(, "输入开口弦长: ")
, y6 t5 D( K$ O/ [- x2 Vaa1 = 1 / aa # \, m/ h, p2 X5 t% a! ^( j4 Z
yy = aa * (ll / 2) ^ 2
a' m* n' p- `; h) sa1 = ThisDrawing.Utility.AngleToReal(-30, acDegrees)
- G- H3 u- _& V' f$ p1 g% Ka2 = ThisDrawing.Utility.AngleToReal(30, acDegrees)
! R H# Z7 u5 ra3 = ThisDrawing.Utility.AngleToReal(90, acDegrees) 5 Y2 S) i* A: C3 K3 L
a4 = ThisDrawing.Utility.AngleToReal(150, acDegrees)
. [& D4 g% ^6 v; K) dbq2 = ThisDrawing.Utility.PolarPoint(bq1, a2, yy) + {1 F3 `7 i- k7 v, e
pt1 = ThisDrawing.Utility.PolarPoint(bq1, a4, aa1)
( ?8 N; O& ^! H( L( j$ apt2 = ThisDrawing.Utility.PolarPoint(bq2, a3, aa1) 2 ?8 Z9 Q5 [; c6 \. E" G
pt3(0) = pt2(0): pt3(1) = pt1(1): pt3(2) = pt1(2) ) Q5 v- S a9 ^, V3 g: E
bq3(0) = bq2(0): bq3(1) = bq2(1): bq3(2) = bq2(2) + 10 3 Y( ?: _1 p: q% Q# u
bq4(0) = bq2(0): bq4(1) = bq1(1): bq4(2) = bq1(2) ( y6 x; n2 u# ?: Z% H6 ~
pt33(0) = 10: pt33(1) = 0: pt33(2) = 0
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ptarr(0) = pt1(0) : i' U& h0 \6 @7 N2 L. b6 L* a7 N
ptarr(1) = pt1(1)
" b! U+ p6 |9 R, E' [ptarr(2) = pt2(0)
: E. H4 f9 b9 G0 O% J7 X. [ptarr(3) = pt2(1) ! D4 v% A, ^ R5 _& Y5 @# Q: f
ptarr(4) = pt3(0) 7 p' [! _, l5 A$ ]
ptarr(5) = pt3(1) 1 g: C, \) Y& N% j+ W- ?$ r
ptarr(6) = pt1(0) + @: h m7 V, o T5 e4 _; d$ r
ptarr(7) = pt1(1)
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0 _/ z' n- k! t! ~+ J9 B'画多段线 1 Y( W/ M" d+ `' \+ O5 T" d0 T
Set lens = ThisDrawing.ModelSpace.AddLightWeightPolyline(ptarr)
3 ?4 E. a& B, d8 [) x. ~Dim objlist(0) As AcadEntity " I5 C! L: j X3 A
Set objlist(0) = lens
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- O2 K; l: c$ Q4 \! r'将多段线变为面域 2 b- B7 X5 ?- G) G; A! c: R; _
Dim altregion As AcadRegion + v" h; I- W* N9 X! ?, I# s3 h( t
alt = ThisDrawing.ModelSpace.AddRegion(objlist)
' {5 d! O- W Y* Mobjlist(0).Delete + J& g4 L: ~" y0 j/ G- e) P6 u
Set altregion = alt(0)
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6 Q- H/ f6 m2 e9 V9 {3 M3 Z) O'旋转面域得到圆锥 ) U& p1 ^$ M6 F
ae = 2 * Atn(1) * 4 L& Y* N2 u' X1 @* L/ s
Set objboltb = ThisDrawing.ModelSpace.AddRevolvedSolid(altregion, pt1, pt33, ae)
) K. [8 {/ p: xaltregion.Delete
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'切圆锥得到抛物线
0 p P+ L0 o% RSet al = objboltb.SectionSolid(bq1, bq2, bq3)
& E# @* R+ }7 K/ Zobjboltb.Delete
% b. i& u I* C* s0 @% {" Fal.Rotate bq1, a1
& b# n/ d; V7 i8 u* x- }al.Rotate3D bq1, bq4, a3 ' e6 \6 J# W- }4 W7 [2 @
Dim explodedobjects As Variant
M) w7 U0 N S, q" y. d6 Zexplodedobjects = al.Explode - ?8 h5 i" q) C ^- x `8 e
al.Delete
5 o! d' C* e- Z+ Q8 ?, J& nDim i As Integer d# Z ^9 R: D% X, D/ q1 E) j
Dim kind As String
7 y, s/ n# E. _/ iDim parabolaobject As AcadSpline + E! P- w* ~ ^( C, n
For i = 0 To UBound(explodedobjects)
8 |$ r. N5 b9 F6 Pkind = explodedobjects(i).ObjectName ) Z: o* C! w3 N6 x2 H$ V
If kind = "AcDbLine" Then
+ ?# E' C7 K. l, C8 j& H explodedobjects(i).Delete 7 P& v, i$ B, L& J/ S; [- ]
Else : J& ~' [. `; X
Set parabolaobject = explodedobjects(i) * C" ^4 o" O4 d
End If
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'旋转抛物线 & ^2 }4 E5 z( R/ I
ThisDrawing.SendCommand "rotate" & vbCr & "(Handent """ & parabolaobject.Handle & """)" & vbCr & "" & vbCr & bq1(0) & "," & bq1(1) & vbCr
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End Sub
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