Hi Nick, well the circles are deleted because they're just one stage of the scripted batch operation that the Pipe command performs.

The Pipe command is just basically a scripted set of actions that you could otherwise do manually, like drawing a circle, sweeping it along the path to make a tube, then drawing another smaller circle and sweeping it also to make a smaller tube if you have an inner radius, and then booleaning out the inner one from the outer one.

It would be kind of weird if a batch operation script like this would leave behind all of the objects from its intermediate calculations, because that would kind of clutter up your model with a lot of additional pieces that you would not really expect to see.

- Michael