31c6db52_GIMP_Selection_Tools__Description
[Tool] Intelligent Sissors [Description] 
This tool is useful when you are trying to select a region defined by strong color-changes at the edges. To use the Intelligent Scissors, you click to create a set of "control nodes", also referred to as anchors or control points, at the edges of the region you are trying to select. The tool produces a continuous curve passing through these control nodes, following any high-contrast edges it can find. Note that this tool doesn't always produce a nice, smooth path. Many experienced GIMP users tend to use the Path tool instead.
GIMP Selection Tools
Description