In the case of this tutorial, first you make a box and set it to wire frame visibility in the viewport.
Then you make a cylindrical pipe section to fit just inside the box, model it to a good shape, and apply the subsurf modifier to it.
The purpose here is to have a tileable modular object to make a network of pipes with.
So it looks like the original box (invisible in the final render) and the cylinder are two objects that travel together and get duplicated all over the place together.
And then you do similar things with different pairs of guide box/pipe section, so you have multiple repeatable parts in the kit.
So doesn’t that entail that each guide box/visible cylinder pair needs to be packed in its own respective collection to act as a single object?
