Lineweights: heavy cuts, light furniture, by layer

One lineweight everywhere makes a plan unreadable.

A printed plan reads at a glance when weight follows importance. Use the ISO pen steps (0.13, 0.18, 0.25, 0.35, 0.5, 0.7 mm): heaviest for what the plan cuts through, lightest for hatches, dimensions and grids. Furniture sits in the middle: 0.35 mm outline, 0.18 mm detail, clearances dashed on their own layer. Set lineweight by layer, keep objects BYLAYER, and pick one plot style type per drawing (CTB by colour or STB by name).