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：
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 loops : for ( variable1 = <range or vector>, variable2 = <range or vector> ) <do something, using both variables>
for loops can be nested, just as in normal programs. A shorthand is that both iterations can be given in the same for statement
| Usage example 1 - iteration over a vector: | |
for (z = [-1, 1]) // two iterations, z = -1, z = 1{
translate([0, 0, z])
cube(size = 1, center = false);} |
|
OpenSCAD iteration over a vector |
| Usage example 2a - iteration over a range: | |
for ( i = [0 : 5] ){
rotate( i * 360 / 6, [1, 0, 0])
translate([0, 10, 0])
sphere(r = 1);} |
|
OpenSCAD iteration over a range) |
| Usage example 2b - iteration over a range specifying an increment: |
// 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.for ( i = [0 : 0.2 : 5] ){
rotate( i * 360 / 6, [1, 0, 0])
translate([0, 10, 0])
sphere(r = 1);} |
| Usage example 3 - iteration over a vector of vectors (rotation): | |
for(i = [ [ 0, 0, 0],
[ 10, 20, 300],
[200, 40, 57],
[ 20, 88, 57] ]){
rotate(i)
cube([100, 20, 20], center = true);} |
|
OpenSCAD for loop (rotation) |
| Usage example 4 - iteration over a vector of vectors (translation): | |
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);} |
|
OpenSCAD for loop (translation) |
Nested loop example
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]);
Iterate over the values in a vector or range and take an intersection of the contents.
Note: 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.
Parameters
<loop variable name>
Name of the variable to use within the for loop.
| Usage example 1 - loop over a range: | |
intersection_for(n = [1 : 6]){
rotate([0, 0, n * 60])
{
translate([5,0,0])
sphere(r=12);
}} |
|
OpenSCAD Intersection for |
| 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);} |
|
OpenSCAD Intersection for (rotation)
原文：http://my.oschina.net/u/2306127/blog/382335
