Rendering issue with latest openscad

[Roxy]

And while I did see a children(); command - not the foggiest what it's doing.

...

So in words of one syllable - what does children do and how do I use it ?

OpenScad compiles everything for every place it is used. But children() is sort of an exception to this. It compiles the code to do the child and then just keeps re-using it for the module referencing the child(). So that dramatically cuts down on the work (and memory) that needs to be done to generate the object you are building.

The syntax for child() is the same as doing simple things like translate([0,0,0]) something(). If you define a module that references a child, then you just say

my_module() the_child_it_references();

And my_module() could go into a big loop placing the_child_it_references() a bunch of times even though it is only calculated once.