Layer Definitions

The Layer definitions settings panel is used to manage layers in your drawing.  This panel lets you can create, modify, rename, show and hide layers.

Layers

Layers are an important concept in CAD.  They are used to logically group objects so that they can be shown or hidden as a set and to define a common style for these objects.

When you create objects using the Draw tools, they are assigned to the current active layer. You can change the active layer by tapping the Layer button in the bottom app bar of each draw tool. The color, line thickness, and line type properties for new objects defaults to a special value called "By Layer" which means that the object is drawing using the layer's properties. Once an object has been created, color, line thickness, and line type properties can be overridden using the Properties tool but it is generally a good practice to avoid such exceptions.

There are three active layer defaults, one for objects created using the draw tools, one for text, and one for dimensions and arrows. It is generally good practice to separate these classes of objects by layer. This is an aid to that end.

This panel allows you to change all of the properties of a layer including its name.  Changing the name of a layer does not alter the set of objects assigned to that layer.  If you assign an object to a layer called "Red", then rename the "Red" layer to "Blue", the object is now assigned to the "Blue" layer. Changing color, line thickness or line type for a given layer will update these properties for every object assigned to that layer.

There is a special layer called "Unassigned" that always appears at the top of the list.  The "Unassigned" layer behaves like other layers in that you can set its display and visibility attributes, however it can not be renamed.  The "Unassigned" layer is very import when creating symbols.  Any objects in a symbol that are assigned to the "Unassigned" layer will be assigned to the current active layer when the symbol is inserted into your drawing.

Layer sample image

When a layer is selected from the layer list in the settings panel, a sample line drawn using the selected layer's properties is shown at the top of the panel. If the layer definition is changed, the sample line is redrawn using the new definition. The layer's name is shown above the line to the left. The number of objects contained on the layer is shown above the line to the right. If the layer is the active drawing, text or dimension layer, that will be noted below the line.

Adding layers

Layers can be added (created) by tapping the Add a new layer button below the list. This will add a single new layer using a default name, color, line type and thickness. These properties can be changed as desired.

Deleting layers

The selected layer can be deleted by tapping the Delete select layer button below the list. Layers can only be deleted if they are empty (i.e. no objects are assigned to that layer). You can't delete the Unassigned layer or the active drawing, text or dimension layers.

The following properties can be defined for each layer:

Visibility

The visibility attribute (designated by the  symbol) controls whether or not the layer is visible. Tapping the  symbol will toggle the visibility property for the selected layer. If the layer is hidden, the  symbol will be dimmed. Hiding the layer will hide all of the objects on that layer. Note that you can't hide any of the active layers.

Layer Name

Layers are identified by name. Layer names are free-form text and can contain any printable characters; however layer names must be unique within your drawing.  You can use any naming convention that makes sense to logically partition your data, however when collaborating with others, standard naming conventions become very important.  There are a number of official and semi-official layer naming standards proposed by various industry groups.  You can search the web for these standards, however this is a good place to start.

Color

The default color for the layer. Objects drawn on this layer will be displayed in this color unless the color propetry is overridden in the object's properties panel. When a new layer is created, the color will imitially be set to the "Default foreground" color, a color that contrasts well with the Theme Background color. Tapping the color control will show the Color Picker dialog which allows you to select a new color for the layer.

Line type

The default Line type (dash pattern) for the layer.  Objects drawn on this layer will be drawn using this line type unless the line type property is overridden in the object's properties panel.

Thickness

The default line thickness for the layer.  The line thickness is measured in paper units. Objects drawn on this layer will be drawn using this line thickness unless the thickness property is overridden in the object's properties panel.