Underlay Perspective Correction
Deskew a photographed flat plan before setting its scale.
Perspective correction helps straighten a flat source photographed at an angle. It cannot recover missing detail or turn a photograph of uneven terrain into an accurate survey.
Load and adjust the source
Open Import → Underlays, load the reference and move to Adjust. Rotate or crop as needed to make the area you are correcting clear.
Set the correction corners
Choose Deskew perspective and move the correction handles to the four corners of the rectangular area that should appear square-on. Check the corrected preview; use Reset perspective to remove the correction.
Calibrate after correction
Go to Size and calibrate a known distance on the corrected image. Inspect another known distance in a different direction to detect distortion. Finish only when the reference is suitable for your purpose.