Each layer can be turned on or off, locked or unlocked, made to display or not display based on specific conditions applied within AutoCAD, and assigned other visual characteristics such as transparency or plot style table color mapping.
When plotting, only objects on visible and unlocked layers will be drawn on the paper by default although these settings, among a number of others, can be controlled through various settings found in the Layer Manager toolbar (LAYERC), Layer Properties Manager toolbar (LAYER) and Plot dialog
