BOSL2/tutorials/Distributors.md
2020-03-30 14:47:50 -07:00

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BOSL2 Distributors Tutorial

Distributors

Distributors are modules that are useful for placing multiple copies of a child across a line, area, volume, or ring. Many transforms have one or more distributive variation.

Transforms Related Distributors
left(), right() xcopies()
fwd(), back() ycopies()
down(), up() zcopies()
move(), translate() move_copies(), line_of(), grid2d()
xrot() xrot_copies()
yrot() yrot_copies()
zrot() zrot_copies()
rot(), rotate() rot_copies(), arc_of()
xflip() xflip_copy()
yflip() yflip_copy()
zflip() zflip_copy()
mirror() mirror_copy()

Transform Distributors

Using xcopies(), you can make a line of evenly spaced copies of a shape centered along the X axis. To make a line of 5 spheres, spaced every 20 units along the X axis, do:

xcopies(20, n=5) sphere(d=10);

Note that the first expected argument to xcopies() is the spacing argument, so you do not need to supply the spacing= argument name.

Similarly, ycopies() makes a line of evenly spaced copies centered along the Y axis. To make a line of 5 spheres, spaced every 20 units along the Y axis, do:

ycopies(20, n=5) sphere(d=10);

And, zcopies() makes a line of evenly spaced copies centered along the Z axis. To make a line of 5 spheres, spaced every 20 units along the Z axis, do:

zcopies(20, n=5) sphere(d=10);

If you don't give the n= argument to xcopies(), ycopies() or zcopies(), then it defaults to 2 (two) copies. This actually is the most common usage:

xcopies(20) sphere(d=10);
ycopies(20) sphere(d=10);
zcopies(20) sphere(d=10);

If you don't know the spacing you want, but instead know how long a line you want the copies distributed over, you can use the l= argument instead of the spacing= argument:

xcopies(l=100, n=5) sphere(d=10);
ycopies(l=100, n=5) sphere(d=10);
zcopies(l=100, n=5) sphere(d=10);

If you don't want the line of copies centered on the origin, you can give a starting point sp=, and the line of copies will start there. For xcopies(), the line of copies will extend to the right of the starting point.

xcopies(20, n=5, sp=[0,0,0]) sphere(d=10);

For ycopies(), the line of copies will extend to the back of the starting point.

ycopies(20, n=5, sp=[0,0,0]) sphere(d=10);

For zcopies(), the line of copies will extend upwards from the starting point.

zcopies(20, n=5, sp=[0,0,0]) sphere(d=10);

If you need to distribute copies along an arbitrary line, you can use the line_of() command. You can give both the direction vector and the spacing of the line of copies with the spacing= argument:

line_of(spacing=(BACK+RIGHT)*20, n=5) sphere(d=10);

With the p1= argument, you can specify the starting point of the line:

line_of(spacing=(BACK+RIGHT)*20, n=5, p1=[0,0,0]) sphere(d=10);

If you give both p1= and p2=, you can nail down both the start and endpoints of the line of copies:

line_of(p1=[0,100,0], p2=[100,0,0], n=4)
    sphere(d=10);

The grid2d() command will let you spread copies across both the X and Y axes at the same time:

grid2d(20, n=6) sphere(d=10);

The spacing can be separately specified for both the X and Y axes, as can the count of rows and columns:

grid2d([20,30], n=[6,4]) sphere(d=10);

Another neat trick of grid2d(), is that you can stagger the output:

grid2d(20, n=[12,6], stagger=true) sphere(d=10);

You can get the alternate stagger pattern if you set stagger="alt":

grid2d(20, n=[12,6], stagger="alt") sphere(d=10);

By default, if you give a scalar for the spacing value, staggering will give you a hexagonal grid, with the spacing being the distance from an item to all six of the surrounding items. If you give the spacing as a 2-item vector, then that will force the X and Y spacings between columns and rows instead.

grid2d([20,20], n=6, stagger=true) sphere(d=10);

You can alternately specify a grid using size and spacing:

grid2d(20, size=100) sphere(d=10);
grid2d(20, size=[100,80]) sphere(d=10);
grid2d(20, size=[100,80], stagger=true) sphere(d=10);

You can also make grids by specifying size and column/row count:

grid2d(n=5, size=100) sphere(d=10);
grid2d(n=[4,5], size=100) sphere(d=10);
grid2d(n=[4,5], size=[100,80]) sphere(d=10);

Finally, the grid2d() command will let you give a polygon or region shape to fill with items. Only the items in the grid whose center would be inside the polygon or region will be created. To fill a star shape with items, you can do something like:

poly = [for (i=[0:11]) polar_to_xy(50*(i%2+1), i*360/12-90)];
grid2d(5, stagger=true, inside=poly) {
    cylinder(d=4,h=10,spin=90,$fn=6);
}

Rotational Distributors

You can make six copies of a cone, rotated around a center:

zrot_copies(n=6) yrot(90) cylinder(h=50,d1=0,d2=20);

To Be Completed