When to use 'Support' option?

[curious aardvark]

don't forget to use 'union'

Basically union glues everything between it's brackets into a single lump that you can then apply any of the other operations to.

And also it's worth knowing that you can apply operations to an entire bracket set.
Took me a while to figure that out.

for example:

difference(){
translate([0,0,10]) cube([20,20,20],true);
translate([0,0,10]) sphere(d=25);
} // end diff

makes my favourite torture test model. Screw benchies if you can print the hollow cube - the machine is dialled in !

So if we want to do something to the whole model we can simply put the operation in front of the difference and it will effecdt everything between the brackets - much like making it aseperate module does. But without the extra hassle.

rotate([45,0,0]) resize([10,40,30]) difference(){
translate([0,0,10]) cube([20,20,20],true);
translate([0,0,10]) sphere(d=25);
} // end diff

So if you've got a section in the middle oif a module you want to change all at once - slap a set of 'union' brackets round it and apply the operations to the union operation :-)

This is particularly useful if you use a 'minkowski' command to round off corners.
Because minkowski takes the degree of roundness form a sphere or a cylinder. It also adds all measurements together and changes the size of the model.
So a resize command before a minkowski command will keep the model the right size and apply more or less curvature depending on the diameter of the cylinder or sphere.

minkowski(){
cube([20,20,20]);
cylinder(d=5,h=1);
} // end mink

versus:

resize([20,20,20]) minkowski(){
cube([20,20,20]);
cylinder(d=5, h=1);
} // end mink

I did read the explanation of how minkowski works. And it involved robots driving around rooms on different vectors and colliding with things - yeah....

Minkowski is a fun command to play with - but it does reqquire some serious calculation - what with all those little robots driving around.
I really need to find that 'explanation' again - it was completely surreal.

It's amazing just how complicated you can get with simple things.

It's also why I always mark what operation the second curly bracket applies to. Otherwise it gets really confusing, really quickly.

It's also why i use very short variable names.
Some calculations for parametric models can contain several sets of bracketed calculations in a single slot. If you use long names for the variables, they become almost impossibly long and damn difficult to read.

For example, this line from a script that makes hinged moulds for clay sling glandes: translate([(gd+hod)/2+hod/2,gl/2+st,gd/2])
Is pretty easy to read.
but if the variables read:
gd=glandediameter,
hod=hingeouterdiameter
gl=glandelength
st=shellthickness
It would be so bloody long the whole thing just looks like a 60's stream of consciousness novel.
And that's just one operation in a line of script that has several, equally convoluted operartions and a shape.

There is frequently/occasionally (delete as appropriate) method to my madness.