Layers in Drafting: Layering in AutoCAD

Why Layers?

Benefits of Mass Property Adjustment

When the properties of geometry need to be modified by the designer, such as the linetype, color, or lineweight, these attributes can be modified by selecting the geometry in question and using the Properties pallet. However, the selection of every piece of geometry manually becomes less efficient the larger and more complex your drawing gets. For example, if you would like all geometry associated with electrical power to be cyan and bold, widespread practice dictates that a layer is to be made with those properties and then place all electrical geometry onto that layer. The layer properties will be inherited by the geometry and will follow the layer’s properties hereafter.

Initial Set-Up

Setting up layers early in the drafting process will put you in the right mindset for keeping track of the items in your workspace. Naturally, the types of layers that will need to be created per drawing vary heavily from project to project. The first two layers to be familiar with are the “0” layer and the “defpoints” layer. These are known as the default AutoCAD layers and will be the first to appear in your layer dropdown. The “0” layer is a fantastic place to start and is where most initial geometry is drawn before being moved to a specific layer. The “defpoints” layer is by default, a non-plotting layer. This means that all elements placed on that layer will not print, regardless of what other visual settings are enabled for that geometry.

Various Layer Uses

There is a vast multitude of reasons to use layers, and all of them are valid if they assist the designer in communicating the project’s intent. Common examples of layer uses are below:

• Construction layers are often used to create geometry that is used as a guide for future planning and drafting. This “scaffolding” layer is often set to not plot and is often frozen towards the end of the project but is critical in the initial stages as the geometry is being developed.
• Different disciplines are often grouped into individual separate layers, allowing for easy selection and manipulation of elements in that discipline, whether these are physical elements on a building’s floorplan, or underground utilities in a site-wide plan.
• Even within a discipline, various features can be further categorized into their own distinct categories. For example, the Civil discipline can be broken down into separate layers for water features, grading lines, and trees. Similarly, the electrical discipline can have sub-categories such as transformers, overhead lines, and panels.

Efficiency Example: Separating Utilities in A Site Plan

For example, if there is specific geometry that is certified to be accurate and should not be accidentally modified, the layer of that geometry can be locked using the LOCK command. If you wish for the content to no longer be visible, then the HIDE command allows for all elements on that layer to be removed from view. Furthermore, the FREEZE command removes the geometry from the drawing until the layer is “thawed,” allowing for smoother operation of larger and more complex drawings. Finally, the selection of elements becomes simplified when they are grouped by layers. Use the QUICK SELECT command to rapidly select all elements that are placed on a specific layer, allowing you to copy, move, or otherwise modify them, no matter how many elements there are. ARY’s “Untangling a Site Plan” demonstrates the benefits of properly using layers for categorization purposes, turning the cleanup and documentation of complex site plans into a straight-forward process.

Paper Space and Viewport Tools

Although most geometry is originally drawn and manipulated in modelspace, there comes a time when the design intent needs to be finally communicated through paperspace plotting. Fortunately, there are additional tools for assisting designers in the categorization and manipulation of geometry based on their layers within the viewport. The command in question is called FREEZE IN VIEWPORT, allowing certain elements to be frozen (hidden) from view in the viewport in question. In modelspace, that layer’s geometry is active and thawed. However, in the specific viewport, the layer if frozen, allowing for a cleaner deliverable. Applying this to the site plan example: there may be a sheet that needs to contain only the above-ground infrastructure – no utilities. In the viewport for the site plan paperspace sheet, use the FREEZE IN VIEWPORT command to freeze all utility layers, ensuring that they will not appear in that specific viewport.

Layers – A Simple, Effective Tool