Layers in ZWCAD are like the transparent overlays you use in manual drafting. You use layers to organize different types of drawing information. In ZWCAD, each object in a drawing exists on a layer. When you draw an object, it is created on the current layer.
You can control the visibility of layers in individual viewports. When you turn a layer off, objects drawn on that layer are no longer visible, and they do not print. Although a layer may be invisible, you can still select it as the current layer, in which case new objects are also invisible until you turn the layer back on. Objects on invisible layers can also affect the display and printing of objects on other layers. For example, entities on invisible layers can hide other objects when you use the Hide command to remove hidden lines.
You can also freeze and thaw layers. Objects drawn on frozen layers do not display, do not print, and do not regenerate. When you freeze a layer, its objects do not affect the display or printing of other objects. For example, objects on frozen layers do not hide other objects when you use the Hide command to remove hidden lines. In addition, you cannot draw on a frozen layer until you thaw it, and you cannot make a frozen layer current.
You cannot freeze the current layer. If you attempt to freeze the current layer, a dialog box appears prompting you to specify a different layer. You also cannot freeze or thaw a viewport layer unless you are working in a Layout tab.
You can lock or unlock layers. The objects on a locked layer are still visible and will print, but you cannot edit them. Locking a layer prevents you from accidentally modifying objects.
Each layer has its own color, linetype, and lineweight. For drawings that use named print styles, layers can also have their own print style. Objects you draw on a particular layer are displayed in the color, linetype, and lineweight associated with that layer unless you override these settings.
LAYER: Manages layers and layer properties
System Variables Reference