Layers and object properties

Layers organize a drawing like stacked transparent sheets: every object is on a layer and, unless the object says otherwise, the layer sets its color, linetype, lineweight and transparency. Turning a layer off, freezing it or locking it affects all its objects at once.

The layer control

The layer control is on the ribbon (Home tab, Layers panel) and on the Layers toolbar of the Classic workspace: the drop-down list with the current layer and, for each layer, the state icons:

Icon	State	Effect
Light bulb	On or off	Objects on a layer that is off are neither shown nor plotted
Sun or snowflake	Thawed or frozen	Like off, and also left out of calculations; the current layer cannot be frozen
Sun with viewport	Frozen in the current viewport	Only in a layout viewport
Padlock	Unlocked or locked	Objects are visible but cannot be selected or modified
Color swatch	Layer color	Click to change it

Choosing a layer in the drop-down list makes it current: new objects are created on it. The current layer is also shown on the status bar.

The Layer Properties Manager

LAYER opens the Layer Properties Manager, a palette with one row per layer and AutoCAD's columns: status, name, on, freeze, VP freeze, lock, color, linetype, lineweight, transparency, plot, new VP freeze and description. Click a column title to sort, select several layers at once, and search by name with wildcards (*, ?).

Filters: property filters (conditions on name, state, color, linetype...) and group filters (a list of chosen layers), in a tree on the left, with the option to invert them.
Layer states (LAYERSTATE): save the settings of all layers so you can restore them later. They are stored in the drawing as in AutoCAD, which lists and restores them.

Layer commands

Command	What it does
LAYMCUR	Makes an object's layer current
LAYMCH	Moves objects to another object's layer
LAYERP	Undoes the last change to layer settings
LAYISO / LAYUNISO	Leaves only the layers of the selection visible, and undoes it
LAYOFF / LAYON	Turns off an object's layer / turns all layers on
LAYFRZ / LAYTHW	Freezes an object's layer / thaws all layers
LAYLCK / LAYULK	Locks or unlocks an object's layer
LAYMRG	Moves the objects of some layers to another one and deletes the former
LAYDEL	Deletes layers together with all their objects
-LAYER	All of the above from the command line (for scripts)

Color, linetype, lineweight and transparency

Each object has four properties that can take a specific value or one of these two:

ByLayer: the object takes the value of its layer. This is the usual choice, and what new objects have at first.
ByBlock: an object inside a block takes the value of the inserted block.

Objects on layer 0 inside a block are drawn with the layer of the inserted block.

Property	Command	Values
Color	COLOR	ByLayer, ByBlock, the 255 index colors (ACI) or an RGB true color
Linetype	LINETYPE	Continuous and the loaded linetypes; more can be loaded from `.lin` files
Lineweight	LWEIGHT	ByLayer, ByBlock or a lineweight in millimeters
Transparency	PROPERTIES	ByLayer, ByBlock or 0 (opaque) to 90 %

The global linetype scale is LTSCALE; the one for new objects is CELTSCALE. The current values are in CLAYER, CECOLOR and CELTYPE. Lineweights are always shown on screen (the LWDISPLAY toggle is not available yet), and when plotting they depend on the plot style table.

To change the properties of objects already drawn, use the PROPERTIES palette or MATCHPROP.

Transparency

Transparency lets what is underneath an object show through: at 50 %, the object is half visible over the background and over whatever is behind it. Object transparency is changed in the Properties palette; layer transparency, in the Transparency column of the layer manager or with the TRansparency option of -LAYER. New objects take CETRANSPARENCY, which starts as ByLayer.

The TRANSP button on the status bar (TRANSPARENCYDISPLAY) shows or hides it on screen; it does not change the drawing.
It is always plotted to PDF, SVG and PNG (there is no option to plot without it).
It is saved in DWG files from version 2004 (group code 440 on objects and AcCmTransparency data on layers); DWG 2000 keeps the layer transparency but not the object transparency.
Multiline text with its own colors inside the text loses its transparency.