patternlab.london VS.

freesewing.eu

Freesewing generates the seam allowances by offsetting from the seam paths. This means that when there is a corner in your pattern and the two offset seam allowances converge, it would require a lot more code to make the offset seam allowance come to a point. Instead, the offset seam allowances come to the end of the seam paths and then are connected in a straight line, making a trimmed or tapered corner.