Smart Trace Region of Interest
Limit new traces to a selected part of the source image.
On Trace, Region of Interest defines where contour tracing can operate. Use it to exclude unrelated parts of a reference image; it is separate from cropping the source.
1
Draw a region
Choose Rect and drag a rectangle, or choose Poly and click its corners. Complete a polygon with a double-click after placing at least three points.
2
Trace within it
Return to Trace mode and click inside the region. Clicks outside it do not start a trace. Check the contour near the region edge, where a shape may be limited by the boundary.
3
Change or clear it
Draw a replacement region or choose Clear ROI. Review existing paths separately; changing the region is not a promise to remove every path you traced earlier.