From the OpenSCAD user manual: "Although infinitely thin, they are rendered with a 1 thickness."
It's just a default thickness used for rendering. If you define a 2D shape, it gets displayed with a 1mm thickness by default, probably for easier visualization.
From the OpenSCAD user manual: "Although infinitely thin, they are rendered with a 1 thickness."
It's just a default thickness used for rendering. If you define a 2D shape, it gets displayed with a 1mm thickness by default, probably for easier visualization.