在Python里应用Openscad实现3D建模(修改简化版)-4
–SolidPython学习笔记3
参考Parkinbotshortcuts.scad做了部分修改使得代码更为简洁易读
以下是对solidpython的readme的学习笔记(其中的部分code进行了简化):
3D螺纹建模初探3
絮絮叨叨
- 到目前我们已经分析了3D螺纹建模的2个解决方案:扭出来和糊出来(好恶俗的名字。。。)
- 从以上的分析中我们应用PY代码初步实现了标准化的(符合ISO261)3D螺纹
- 接下来我们探讨目前最为流行的方案,并进一步实现定制
方案三:垒出来 Solution Three: Sweep polyhedrons
- 该方案是目前thingiverse上最为流行的方案包括:
- 该方案首先创建一个多面体,然后螺旋堆叠出来一个巨大的多面体
- 这个方案不太好懂,以上几种方案中第一和第二个方案(较早)的螺纹建模(姑且叫衰人(Poorman)方案吧)是一样的,而Poorman的作者aubenc提到了更早的第3个方案
- 以下就是
衰人方案:
scad代码:
module full_thread (ttn,//ttn=round(length/P)+1;圈数
st, //P
sn, //sn=floor(Dmaj*pi/fs);fs=pi/2 sengments 圆段数
zt, // zt=P/fn
Ifxy, //angle_xy=360/fn;
or, // Rmaj
ir //Rmin
)
{
if(ir >= 0.2)
{
for(i=[0:ttn-1])
{
for(j=[0:sn-1])
{
pt = [[0,0,i*st-st],
[ir*cos(j*angle_xy), ir*sin(j*angle_xy), i*st+j*zt-st ],
[ir*cos((j+1)*angle_xy), ir*sin((j+1)*angle_xy), i*st+(j+1)*zt-st ],
[0,0,i*st],
[or*cos(j*angle_xy), or*sin(j*angle_xy), i*st+j*zt-st/2 ],
[or*cos((j+1)*angle_xy), or*sin((j+1)*angle_xy), i*st+(j+1)*zt-st/2 ],
[ir*cos(j*angle_xy), ir*sin(j*angle_xy), i*st+j*zt ],
[ir*cos((j+1)*angle_xy), ir*sin((j+1)*angle_xy), i*st+(j+1)*zt ],
[0,0,i*st+st]];
polyhedron(points=pt,faces=[[1,0,3],[1,3,6],[6,3,8],[1,6,4], //changed triangles to faces (to be deprecated)
[0,1,2],[1,4,2],[2,4,5],[5,4,6],[5,6,7],[7,6,8],
[7,8,3],[0,2,3],[3,2,7],[7,2,5] ]);
}
}
}
else
{
echo("Step Degrees too agresive, the thread will not be made!!");
echo("Try to increase de value for the degrees and/or...");
echo(" decrease the pitch value and/or...");
echo(" increase the outer diameter value.");
}
}
- 我们看一下生成的螺纹的截面:
- 可以看出仍是个伪标准螺纹,我们在下面的scad代码中修改一下
- Or = Rmaj + 1 / 8 * H
- 应用布尔运算修改
衰人方案ISO标准修订版之scad代码
use <shortcuts.scad>;
use<Nut_Job.scad>;
Dmaj = 10;
P = 1;
H = .866 * P;
$fn = 36;
length = 10;
Rmaj = Dmaj / 2;
Rmin = Dmaj / 2 - 5 / 8 * H;
Od = Dmaj+H/4
projection(){
Ry(90)
I(){
U(){
Tz(.5*length)Cy(r=Rmin, h=length);
screw_thread(Od,1,30,10,PI*5/18,0);
};
Tz(.5*length)Cy(r=Rmaj, h=length);
}
}
- 当然了还有一种方法就是直接修改多面体参数(比如:Po,Fa)
衰人方案ISO标准修订版之python代码:
from solid import *
from solid.utils import *
import viewscad
r = viewscad.Renderer(openscad_exec=r'/Applications/OpenSCAD.app/Contents/MacOS/OpenSCAD')
Dmaj = 10
P = 1
H = .866 * P
segments = 60
length = 10
Rmaj = Dmaj / 2
Rmin = Dmaj / 2 - 5 / 8 * H
def thread_p(Dmaj=10,P=1,length=10):
angle_xy = 2 * pi / segments
zt = P / segments
ttn = round(length / P)
p3 = 0
c = []
for i in range(0,ttn):
for j in range(0,segments):
Po = [ [ 0, 0, i*P+ P ],#中轴上
#近截面
[Rmin*cos( j *angle_xy), Rmin*sin( j *angle_xy), i*P+ 1/2 *P + j *zt],
[Rmin*cos( j *angle_xy), Rmin*sin( j *angle_xy), i*P+ 3/8 *P + j *zt],
[Rmaj*cos( j *angle_xy), Rmaj*sin( j *angle_xy), i*P+ 1/16 *P + j *zt],
[Rmaj*cos( j *angle_xy), Rmaj*sin( j *angle_xy), i*P- 1/16 *P + j *zt],
[Rmin*cos( j *angle_xy), Rmin*sin( j *angle_xy), i*P- 3/8 *P + j *zt],
[Rmin*cos( j *angle_xy), Rmin*sin( j *angle_xy), i*P- 1/2 *P + j *zt],
#远截面
[Rmin*cos((j+1)*angle_xy), Rmin*sin((j+1)*angle_xy), i*P+ 1/2 *P +(j+1)*zt],
[Rmin*cos((j+1)*angle_xy), Rmin*sin((j+1)*angle_xy), i*P+ 3/8 *P +(j+1)*zt],
[Rmaj*cos((j+1)*angle_xy), Rmaj*sin((j+1)*angle_xy), i*P+ 1/16 *P +(j+1)*zt],
[Rmaj*cos((j+1)*angle_xy), Rmaj*sin((j+1)*angle_xy), i*P- 1/16 *P +(j+1)*zt],
[Rmin*cos((j+1)*angle_xy), Rmin*sin((j+1)*angle_xy), i*P- 3/8 *P +(j+1)*zt],
[Rmin*cos((j+1)*angle_xy), Rmin*sin((j+1)*angle_xy), i*P- 1/2 *P +(j+1)*zt],
[ 0, 0, i*P- P ]#中轴下
]
Fa =[ [0,1,2,3,4,5,6,13],[13,12,11,10,9,8,7,0],
[7,1,0] ,[13,6,12],
[2,1,7,8] ,[8,9,3,2],
[4,3,9,10] ,[5,4,10,11],
[6,5,11,12]
]
if j == 0 and i == 0:
p3 = bac(P3(Po, Fa))#1st P3
# p3 += C("red")(Rx()(Le(.1)(Pr()(Rx(90)(P3(Po, Fa))))))# sector of 1st P3
# c = 0
for x in range(0,len(Po)):
p3 += translate(Po[x]) (C("red")(Sp(.05)))#Po
p3 += translate(Po[x]) (Le(.01)(text(text= str(x),size=.2))) #num of Po
c += P3(Po, Fa)
# c += Rx()(C("red")(Le(.1)(Rx()(c))))#run the projection() too slow
return p3, c
c = thread_p()[0]
# scad_render_to_file(c, "thr_p.scad")
# r.render(c)
c
这是第一个修改后的多面体
c = thread_p()[1]
c
生成的螺纹
c = Pr()(Rx()(c))
c
螺纹截面