Step-by-Step Guide to Layer Management in CAD

Layers help designers create and modify technical drawings seamlessly, no matter how complex they are. For layers to be effective, they must be managed properly. This article is a step-by-step guide to CAD layer management, explaining what a layer is, its history, benefits, and how to create layers in various CAD software including AutoCAD, BricsCAD, ArchiCAD, Vectorworks, DraftSight, SolidWorks, and Solid Edge. It also delves into how to organize objects using features like filters and groups, control the visibility of layers, and use layers in collaborative projects, as well as the best practices for layer management in CAD. Let’s get started.

Understanding Layers in CAD

What is a Layer in CAD?

A layer can be described as an overlay or level that handles or holds information or objects with similar attributes or functions. These overlays and levels can be turned on or off, helping designers organize their drawings and avoid clutter. They are useful when working on both complex and relatively simple drawings. And as we detail later, they offer multiple benefits.

Layers are used in 2D drawings or 2D CAD drafting. And although 3D modeling software like SolidWorks supports CAD layer management, they do so within a restricted environment. You can only create or manage layers in SolidWorks when working with a 2D drawing. More on this below.

History of Layers in Drafting and Design

Layering and the use of layers existed even before the history of CAD started taking shape; layering preceded CAD. Then, drafters and designers would draw different aspects of a design project on different sheets of paper that would then be overlaid one on top of the other. They used translucent sheets of paper or, in some cases, a type of paper called vellum. 

The translucence ensured that the drawing(s) underneath could still be visible even after overlaying them with other layers of drawings. Layering using vellum or translucent paper enabled drafters and designers to compare various aspects of the design project. The final drawing was created by overlaying all the sheets of paper. 

Taking the example of a house, designers would overlay the floor plan with the mechanical, electrical, and furniture plans. In this example, the designers would be working with four layers of drawings. This way, they could coordinate all these plans (drawings) as though they were a single drawing, making their work easier.

The 1980s ushered in the age of computer-aided design (CAD), with some of the now-most popular CAD software being released in that decade and the next. CAD simplified drafting and introduced a better implementation of layers. Today, many agree that layering is a key advantage of CAD over manual drafting.

Layers help reduce the complexity of technical and detailed engineering drawings, which typically capture a lot of information. Layering splits such complex drawings into multiple layers. Each layer can be turned on or off, locked or unlocked, frozen or thawed at will. 

Benefits of Layers in CAD

Layering allows designers to group objects with similar attributes, offering several benefits:

1. Better control over drawing: Locking layers helps designers avoid making accidental changes
2. Enhanced performance: Freezing layers improves performance as it forces the software to release the layer from memory, freeing up computer RAM
3. Improve coordination and analysis: One of the best practices in CAD layer management is to group similar drawing information in a single layer, which enables better coordination between and among various disciplines. For instance, HVAC ductwork can be placed in a layer named HVAC, while electrical wiring can be located in a layer called ELEC. As a result, the electrical team only needs to turn on this layer to understand how the wiring interacts with other parts of the drawing, such as the floor plan, and perform any requisite analyses. 
4. Reduce visual complexity: Layers reduce the complexity of technical drawings by enabling designers and drafters to hide information they don’t need to view.
5. Better overall organization: Layers help designers organize the multiple objects in their drawings by the commonality of purpose or function.

Layer Management in CAD

CAD layer management encompasses processes and tools for creating, naming, renaming, and deleting layers, as well as the following:

• Setting layers as current
• Changing layer properties such as color, line weight (line thickness), linetype, transparency, material, and much more
• Controlling whether or not the objects in a layer are to be plotted; this CAD layer management tool is called plot or no-plot in AutoCAD and print or no print in BricsCAD
• Grouping/merging layers and removing layers from a group
• Removing unused layers from the current drawing using the Purge command, ergo optimizing CAD file size
• Toggling visibility on or off
• Locking or unlocking layers to prevent or allow editing
• Freezing or thawing layers
• Selecting the layer type (this depends on the software)
• Setting layer filters to limit the number of layer names displayed in the Layers window/dialog box or, in the case of AutoCAD, the Layer Properties Manager
• Choosing the layer standards to use

Setting Up Layers in a CAD Project

Layers in AutoCAD

AutoCAD simplifies CAD layer management. It has a dedicated Layers ribbon panel in the Home ribbon tab, which offers quick access to some of the most important CAD layer management tools and icons. In addition, it features a bar that shows you the current layer. This ribbon also features the Layer Properties button that opens the Layer Properties Manager that, as the name states, lets you manage all your layers. The Layers ribbon panel displays some of the information contained in the Layer Properties Manager.

Layers in ArchiCAD

To create and manage layers in ArchiCAD, click Options > choose Element Attributes > click Layers on the Element Attributes’ contextual menu. Alternatively, you can use the shortcut Ctrl+L or click the Layer Settings icon in the Quick Options bar. These steps open the Layers dialog box in ArchiCAD, which, in turn, enables layer management in CAD.

Layers in SolidWorks

In SolidWorks, you can create layers in 2D drawings and adjust their properties such as line style, thickness, visibility, and color. 

To create drawing layers in SolidWorks, first turn on the Layer toolbar (if not on already) by clicking Linear Sketch Patterns > Toolbars >  toggle on the Layer option. Next, click the Layer Properties icon in the Layer toolbar, which opens the Layer dialog box. 

The Layer dialog box has several CAD layer management tools like New, Delete, and Move. This dialog box also lets you change layer properties.

Layers in DraftSight

DraftSight offers three different ways of opening the Layers Manager palette, which enables CAD layer management. You can type Layer or click Format > Layer or click Home > Layer > Layers Manager. With the Layers Manager palette open, you can create a new layer, delete layers, set the active layer, apply layer states, search for layers, and so on.

Layers in SketchUp

You can create and delete layers in SketchUp. The software also enables you to add or move objects to a particular layer, lock layers, or modify the layer’s visibility. You can also change a layer’s type from regular to shared layers and vice versa. This means SketchUp supports two types of layers:

• Regular or non-shared layer: It restricts objects and elements to only one page, helping you control the visibility of the content in your document.
• Shared layer: It displays objects and elements on every page of your document.

To create a layer in SketchUp, click the Layers panel on the Default Tray to the right of the user interface > select the Add New Layer button. You can name the layer by double-clicking the default name, which enables you to type a new name for the layer. Press Enter to set the name.

Layers in Solid Edge 2D Drafting

Solid Edge 2D Drafting is free software for creating 2D designs. It offers plenty of features for drafting, annotations, and dimensioning. It also supports global and national drafting standards. As a 2D drafting software, it offers CAD layer management, which can be easily accessed by clicking the Layers tab to the right of the window (user interface). Doing this opens the Layers dialog box that lets you create new layers, set the layer as current, and much more. 

Layers in LibreCAD

LibreCAD simplifies layer management with the default Layer List widget. However, you can change the widget’s position if you so wish. The Layer List widget lets you create new layers, delete layers, lock or unlock, toggle the visibility on or off, or control whether the object will be printed. It also enables you to change the layer properties.

Layers in BricsCAD

BricsCAD supports layers. It lets you create and manage layers (delete, rename, merge/group, and remove from group). You can also make a layer current. To create and manage layers in BricsCAD, simply use the EXPLAYERS command to open the Drawing Explorer dialog box with the Layers category selected. It is the Drawing Explorer dialog box that enables CAD layer management.

Layers in Vectorworks

There are two types of layers in Vectorworks:

• Sheet layers help designers create presentation versions of a completed drawing. Sheet layers have a 1:1 scale and can include viewports, notes, title block borders, and other annotations.
• Design layers contain drawing items and are used to draw and model various elements of a design project. Design layers can be reordered, hidden, scaled, or stacked.

Vectorworks supports multiple ways of creating a new layer. You can click Tools > Organization (which opens the Organization dialog box) > click the New button on the Design Layers or Sheet Layers tab. Alternatively, click View > Layer Options > select New Design Layer or New Sheet Layer. You can check the other procedures for setting up new layers on the Vectorworks help page.

Like the other CAD software on this list, Vectorworks allows you to set the active layer. You can set or change the properties of the design: color, opacity, and stacking order of the design layer. You can set the sheet layer properties by changing the stacking order, description, raster rendering DPI, and sheet title, among others.

Organizing Objects by Layers

Different CAD software implement layering in various ways without a universal method for creating layers. So, you have to know the procedure to set up layers in the software you use.

Similarly, the procedures for creating layer filters, setting layers as current, assigning objects to layers, and grouping layers will vary from one software to another. But now that you already know how to open the layer window/dialog box (known as the Layer Property Manager in AutoCAD, Drawing Explorer dialog box with the Layers category selected in BricsCAD, and so on), it is nonetheless easy to organize objects by layers. Simply open this box and select the CAD layer management function you want to use.

Layer Filters

Technical drawings can have dozens or even hundreds of layers, though not all are always necessary. Additionally, going through each of these layers one by one to get to the one you want to set as current is inefficient. For these reasons, the layer filter exists to limit the number of layers displayed in your layers dialog box/window. You can choose the criterion using which the software will filter the layers. For instance, you can base this criterion on layer properties like color or name.

Group Layers

BricsCAD lets you merge multiple layers into one layer. This feature lets you choose a target layer into which the other layers will be merged. This feature helps you reduce the number of layers. The software also allows you to remove layers from a group. You can also create group filters. BricsCAD also lets you convert a property filter to a group filter.

Set Layer as Current

Setting a layer as current ensures that all new objects are automatically assigned to it. To set a layer as current, simply click on a particular layer. You can also move the existing object(s) from one layer to another by first selecting the object(s) you want to move and then choosing the new layer you want to assign to the object(s). 

However, this procedure does not apply universally to all CAD software. SketchUp, for example, has a different procedure for moving object(s) from one layer to another, as detailed here.

Controlling Layer Visibility and Modification Capabilities

As stated earlier, technical drawings can be extremely complex owing to the volumes of information they capture. Layers manage complexity by allowing you to control their visibility and editing permissions.

Layer Visibility

There are two ways of controlling visibility on software:

• Turning a layer on and off: Turning a layer off makes the objects on this layer invisible to the eye. On the other hand, turning a layer on makes the objects on that layer visible once again.
• Freezing and thawing layers: When you freeze a layer, you prompt the software to force-release it from the memory and hide it from view. This way, freezing boosts software performance by ensuring only the necessary layers are loaded and displayed. You will notice that the drawing regenerates much faster than before. Thawing recalls the layer to memory and makes it visible.

You can turn a layer on or off and freeze or thaw a layer using the various options on the layer window. Simply click on the ‘eye’ icon or ‘bulb’ to turn it on (if it was off) or off (if it was on). A ‘snowflake’ icon represents the freeze buttons in AutoCAD and BricsCAD; to freeze a layer, simply click this button. A ‘sun’ icon represents the thaw button in AutoCAD; clicking this button prompts the software to thaw the layer. On BricsCAD, you don’t have to click a dedicated button to thaw a layer; instead, simply toggle off the freeze button.

Lock and Unlock Layers

Locking a layer prevents accidental edits. By default, AutoCAD displays locked layers using a faded color. This way, it still enables you to view the object, albeit in a manner that reduces the visual complexity of the drawing. The only drawback is that the fading feature lowers the visibility of transparent objects. The software, nonetheless, allows you to change the fading levels. On the other hand, unlocking a layer enables you to edit that layer.

Layer Management for Collaboration and Printing

Layer Management for Printing

Software like AutoCAD, LibreCAD, and BricsCAD include a setting that allows you to control whether an object will be printed/plotted or not. This software captures this setting using the printer icon. If you toggle on this setting, the object will be printed, with the inverse being true. 

However, not all software applications support this feature. Fortunately, software programs like Vectorworks have a workaround. If you don’t want some of the objects in your drawing to be printed, you could set the visibility of the layers to invisible. This setting will not only hide the object from view but also block the printer from printing it.

Layer Management for Collaboration

Large-scale CAD projects involve team collaboration. However, a common theme is that such teams may not always share workflows, particularly as it relates to the software used. This means that while one team prefers using one software to design products, the other team may be drawn to another. Fortunately, there are plenty of real-time collaboration tools in the market today. Some CAD software also ships with certain built-in features that enable cross-software collaboration, i.e., collaborative design. One of these features is XREF.

Short for External Reference, XREF allows you to attach drawings, images, PDFs, and point cloud data to your drawing. This feature also has built-in capabilities to import layers from the attached drawings. Using XREF to import layers can promote uniform implementation of layering. 

The direct result of the cross-referencing is that teams can better understand the drawings without needing additional information or keys. This ensures smooth collaboration, even on large projects. You can complement the XREF feature with CAD standards for layer naming and content, further helping teams align certain aspects of their workflows.

Best Practices for CAD Layer Management and Maintenance

1. Set up layers before starting a drawing to streamline object assignment and maintain clarity. If you’re using SolidWorks, you can use the available CAD layer management tools to create these layers in your drawing template. You can then set up the ability for SolidWorks to automatically apply these settings in subsequent drawings that use this template. You can achieve these by clicking System Options > selecting the Document Properties tab > assigning a layer to the various objects under Drafting Standard, including dimensions, tables, annotations, and view.
   
   
   

   Document Properties Window in SolidWorks for CAD Layer Management

2. Group layers with similar attributes or purposes to avoid cluttering the CAD layer management palette, panel, or window.
3. Use CAD standards for layers, which specify how to name the layers and the content to use. Standardization of CAD layer management is vital for large-scale CAD projects, which bring together several teams and can include complex technical drawings – more on CAD standards for layers below.
4. Bear in mind that colors can affect the quality of lines, especially because they control line thicknesses when plotting.
5. Delete unused layers to reduce file size. You can use the PURGE commands in AutoCAD.

CAD Standards for Layers

Multiple national and international CAD standards and guidelines include specifications for layers. For instance, ISO 13567-1, initially defined in 1997 to harmonize the policies that had been advanced before then, is the international standard for organizing and naming layers for CAD. Others include the AIA (American Institute of Architects) CAD Layer Guidelines: U.S. National CAD Standard and the AEC (UK) CAD Standard, which is based on BS1192. 

Standards for Layer Naming Format

The AIA CAD Layer Guidelines recommend the layer name format detailed in the image below. A hyphen separates each field. The Discipline Designator is mandatory and details the discipline for which the layer is used. For instance, architectural objects are represented by the discipline designator A. The second field, Status, offers more information about the data contained on the layer. For instance, A stands for Abandoned, while D stands for Demolish. 

The mandatory Major Group is a four-character field. It identifies a major building system such as a wall, door, floor, furniture, etc. The optional Minor Group offers more information about the Major Group. 

AIA CAD Layer Name Format

Across the Atlantic in the UK, the AEC (UK) Protocol for Layer Naming outlines five hyphen-separated fields. The first field contains information about the Role, akin to the Discipline Designator in the AIA CAD Layer Guidelines; it’s mandatory and uses one to two characters. 

The second field uses more than five characters and is mandatory; called Classification, it captures information that helps users identify the content of the layer. The fourth single-character mandatory field is called Presentation, while the fifth equally mandatory field is designated Description. The fifth field has a variable length. The fifth and final field is called the View field. 

Conclusion

Effective CAD layer management boosts productivity and simplifies creating complex drawings. This is because layers can be used to hold objects with similar attributes. They allow designers to hide, lock/unlock, or modify properties of the layers uniformly using one or two clicks rather than working on each object individually. In addition, turning the visibility of layers off declutters the drawing, hiding objects that may not be momentarily needed. CAD layer management tools in CAD ensure that these benefits apply to others, especially when you are working collaboratively with others. For instance, the XREF feature imports layers, ensuring everyone uses the same layer naming format. That said, you can refer to your country’s national CAD standard for information on how you can name your layers.