OpenSCAD通过循环快速复制几何对象
OpenSCAD支持变量和循环，从而可以快速复制出大量的几何对象并且按照递归的方式进行布局。
循环的变量可以是枚举、区间和矢量对象，循环体支持几何对象构建、坐标平移与旋转、交并差等操作。
循环的递归变量类型
Vector（矢量）:
for (variable=<vector>) ｛ <do_something> - <variable> is assigned to each successive value in the vector ｝
Range（区间、范围）:
for (variable=<range>) ｛ <do_something> ｝
Nested（嵌套） :
for ( variable1 = <range or vector>, variable2 = <range or vector> ) ｛ <do something, using both variables> ｝
for 循环可以进行嵌套，就像普通程序一样。
使用枚举型矢量的循环
| Usage example 1 - 通过vector的循环调用 | |
for (z = [-1, 1]) // 两个变量, z = -1, z = 1
{
translate([0, 0, z])
cube(size = 1, center = false);
} |
|
使用范围型变量的循环 |
| Usage example 2a - 通过范围实现循环 | |
for ( i = [0 : 5] )
{
rotate( i * 360 / 6, [1, 0, 0])
translate([0, 10, 0])
sphere(r = 1);
} |
|
使用范围型给定步长的循环 |
| Usage example 2b -指定步长和范围的循环 |
// Note: The middle parameter in the range designation
// ('0.2' in this case) is the 'increment-by' value
// Warning: Depending on the 'increment-by' value, the
// real end value may be smaller than the given one.
//类似于c语言的for(i=0;i<5;i+=0.2)...
for ( i = [0 : 0.2 : 5] )
{
rotate( i * 360 / 6, [1, 0, 0])
translate([0, 10, 0])
sphere(r = 1);
} |
| Usage example 3 - 通过矢量的循环 (旋转) | |
for(i = [ [ 0, 0, 0],
[ 10, 20, 300],
[200, 40, 57],
[ 20, 88, 57] ])
{
rotate(i)
cube([100, 20, 20], center = true);
} |
|
通过矢量数组的枚举型循环 |
| Usage example 4 -矢量数组的循环(位移): | |
for(i = [ [ 0, 0, 0],
[10, 12, 10],
[20, 24, 20],
[30, 36, 30],
[20, 48, 40],
[10, 60, 50] ])
{
translate(i)
cube([50, 15, 10], center = true);
} |
|
循环的嵌套和多变量 |
嵌套循环的例程
for (xpos=[0:3], ypos = [2,4,6]) // do twelve iterations, using each xpos with each ypos translate([xpos*ypos, ypos, 0]) cube([0.5, 0.5, 0.5]);
循环的切割
所有的循环（包括枚举值、范围、矢量、矢量数组）都支持几何实体的 intersection 操作。
注意: intersection_for() is a work around because of an issue that you cannot get the expected results using a combination of the standard for() and intersection() statements. The reason is that for() do a implicit union() of the contents.
参数
<loop variable name>
Name of the variable to use within the for loop.
| Usage example 1 - 范围循环: | |
intersection_for(n = [1 : 6])
{
rotate([0, 0, n * 60])
{
translate([5,0,0])
sphere(r=12);
}
} |
|
Intersection for使用示例： |
| Usage example 2 - rotation : | |
intersection_for(i = [ [ 0, 0, 0],
[ 10, 20, 300],
[200, 40, 57],
[ 20, 88, 57] ])
{
rotate(i)
cube([100, 20, 20], center = true);
} |
|
