When to use 'Support' option?

[curious aardvark]

Now you're getting it :-)

If you bear in mkind how a 3d printer works whilst you are designing. You pretty much never need to use supports.

You can build out oir in at up to a 45 degree angle, beyond that it tends to get ugly.

here's an example I knocked up monday:

$fn=50;
difference(){
union(){
difference(){
cube([100,40,30],true);
translate([0,0,2])cube([96,36,30],true);
} // end diffe


translate([40,18,0]) resize([14,8,14])sphere(d=5);
translate([-40,18,0]) resize([14,8,14])sphere(d=5);
} // end union

translate([40,20,0]) rotate([90,0,0]) cylinder(d=10.4, h=3.25);
translate([-40,20,0]) rotate([90,0,0]) cylinder(d=10.4, h=3.25);
translate([0,30,0]) cube([100,20,30],true);
} // end diff

Now the code isn't pretty - cos I just wanted a box I could glue magnets to and attach to metal things like a magnetic window box.
The magnets are 10mmx3mm

If i'd just popped a cylinder into the sdie of the box. it would have needed supports.
So being a sneaky bugger I used a flattend sphere and popped the magnet socket into that.

side magnet box .jpg

The result being a box that has two magnets flush with the side that can be printed cleanly at 0.3mm layer height and - on the sapphire pro - 150mms
With no supports needed.

The magnets are a fairly loose fit - as I glued them. I could have made the hole diameter smaller and used a press fit. But I wasn't sure about applying pliers to the sockets so just used glue.
They are great bits of kit - really useful, don't know why i didn't think of it years ago.

But that's the beauty of 3d printing.
You can design something that does the same job as an injection moulded part. But designed specifically to be 3d printed.

Your homework - make the box parametric :-)
lol