Why did my toolpaths break or come up empty after I nested my parts?

Why it happens

A toolpath normally remembers the exact vectors you selected when you made it. Ordinary edits keep that link alive: move, resize or node edit a vector, recalculate, and the toolpath follows. Nesting is different. As the Learn Your CNC tutorial explains, the nesting tool removes the original shapes and lays down new copies in the nested positions. The toolpath is still pointing at vectors that no longer exist, so recalculating fails or produces nothing. Any operation that replaces a vector with a new one has the same effect.

How to fix it

One-time repair:

1. Double-click the broken toolpath to edit it.
2. Select the nested vectors it should cut.
3. Click Calculate. Repeat for each toolpath.

Better repair, so it never happens again:

1. Before nesting, put each kind of geometry on its own layer (outside profiles, pockets, drill holes and so on).
2. Edit each toolpath and open its vector selection settings (the Selector).
3. Switch from manual selection to automatic: choose the vector type, for example closed vectors, and the layer it should read.
4. Associate that selection with the toolpath and close the selector.
5. Calculate.

Now the toolpath chooses its vectors by rule, so anything that lands on that layer is picked up, including the fresh copies nesting creates. After nesting, run Recalculate All Toolpaths and everything follows the parts.

How to confirm it is fixed

Nest again or move a part, run Recalculate All Toolpaths, and reset and rerun the preview. Every part is cut in its new position and no toolpath reports an error.

Pro tips

• Nest first, toolpath second, whenever you can. It avoids the problem entirely.
• For multi-sheet jobs, save the working set as a toolpath template and load it on the other sheets (see the entries on toolpath templates and the Vector Selector, and on multi-sheet nested jobs).
• Recalculate All Toolpaths is also the right move after changing material thickness or job size.
• The same trap catches the Offset tool: the offset line is a new vector, so a toolpath only picks it up if it sits on a layer the toolpath reads.
• Recalculating changes the toolpath in the job, not the file on your machine's computer. Save the toolpath file again afterwards and check its date before you cut.