Feedback from BrickWorld- in custom shape menu add measurement by baseplate. This might be hard unless you define 32x32 stud baseplate or something.

This arose from a confusion between making custom baseplates and shapes.

Ultimately, custom baseplates are the same as shapes, but have studs on them. The user more wanted to make a custom shape that USED baseplates as a measurement. But we would definitely have to define what size baseplate if we made this.