Stock curve applies only to Z level rough operations. It applies to features that are designated as bosses or pockets on the Strategy page. For boss features, the stock curve sets the outer boundary of the boss feature. For pockets, it creates the toolpaths in a subregion.
Stock curves are selected in the using the select curve dialog box. See Methods of selecting curves in the select curve dialog box for further information.
The figure on the left shows a feature cut without a stock curve. Notice that the toolpaths extend to the stock boundaries. In the figure on the left a circular stock curve is used.