Line thickness is not visible in the user interface

Problem description:

Is there a setting to make thick lines (profile lines) visible in drawings? For example, so that on the screen a line with a width of 0.5 appears thicker than the others.

Answer:

Lines are displayed either thin or thick depending on whether they exceed the default thickness assigned to the line (see image below). This does not affect printing — only how the line appears on the screen.

Select File > System Settings > Mechanical Design