Employing CAD Blocks Effectively in Everyday Design

A CAD manager sets out to provide his team with the best online CAD blocks, parts and model libraries as well as other CAD related resources.

As a CAD manager for Advanced Technical Services, a CAD drafting and design firm located in Lincoln, Nebraska, one of my responsibilities is to ensure my team has the tools they need to do their job accurately and efficiently. CAD blocks, also referred to in some instances as model libraries, standard part libraries or just blocks, are one of those tools that can help accomplish that. A CAD block is a named object, or group of objects, that can be drawn in 2D or modeled in 3D and then used to create repeated CAD content such as drawing symbols, standard details, common parts or other objects used repeatedly within a drawing or model. Think of CAD blocks as content macros. 

For instance, on a typical residential floor plan, there could be several doors within the plan that are the exact same type and size. On a commercial plan, that number could be much higher. I would use CAD blocks to reproduce those doors instead of drawing a new one each time—saving me both time and money. Multiplying these savings of time and money across an entire team over an entire year provides an enormous benefit.

It’s a great value to your design team if validated CAD blocks are readily available in well-thought-out and organized libraries. Adding a resource guide for your team that can direct them to where different blocks, parts or resources are located (along with additional information including when and how to use them) is a powerful tool for your CAD standards toolbox.


Benefits of CAD Blocks

Reduce Repetitive Tasks—Anytime you need to use an object or part multiple times in a drawing, you should be using blocks. Blocks cannot only save time when initially creating objects, they can save you time when revisions are required as well. Let’s say I’ve just completed a large commercial architectural floor plan and the owner decides to change the type of water closet used in all the bathrooms throughout the building. There is no need to revise every water closet one at a time. All I have to do is change the block in Block Editor and the block is updated everywhere it is used in the drawing.

Accuracy—Assuming that you are starting with an accurate CAD part or block, using that same CAD part or block throughout a drawing or model ensures consistency, eliminating potential mistakes that can come from having to redraw the item each time. Also, when designing with complex parts, being able to download the part or model you need directly from a manufacturer or supplier means that you have accurate size and specification information to use in your design.

Reduced File Sizes—File size is reduced by instancing content instead of redefining object data for every instance a block is used. Your CAD program only needs to know the insertion point and rotation, reusing the object geometry from the original block. This can make a huge difference in performance when working with large projects.

Maintain Consistency—Having a set of CAD standards ensures your drawings and models are being presented in a concise and consistent way. Having your title blocks, plumbing fixtures, piping symbols and fasteners presented consistently from one drawing to another, regardless of which CAD user worked on them, is a very important factor in increasing the efficiency and reducing the potential for error in your drawings.

Block Attributes—Many blocks can contain metadata information called attributes. This could be information such as title block information, asset tracking numbers, or manufacturer information such as part number, model or weight. This data can be linked to an Excel database and extracted to create reports, bills of material and schedules.


Type of CAD Block and Part Libraries

  • User-created CAD block libraries: These would be internal user-generated blocks, parts and models that are stored in a common location for users to access across your organization.
  • Block libraries included with CAD programs: Many CAD programs such as AutoCAD, Revit and SOLIDWORKS come with a limited amount of built-in blocks, parts or models for you to use.
  • Third-party add-on programs: These include both free and commercially licensed programs with libraries that run alongside your CAD software or programs that help you organize and manage your own blocks.
  • Block, part and model download websites: These include sites that have single blocks or entire libraries that are available either for free or as a paid download.
  • Manufacturer or reseller websites: Many companies also offer blocks for the products they produce or sell. Downloading these blocks allows designers and engineers to have the exact technical specifications of the part(s) they are using for their design. These can be industry specific, so be sure to keep that in mind when searching online.


Recommended Resources and Block and Part Libraries

A few years ago, I developed a standard document that lists all of our CAD resources, both internal and external, for use by all of my CAD users to quickly and easily access over the network. The document catalogs information on all of the associations we are affiliated with as well as links to other CAD-related sites and resources. Combining my original document with newly researched information available online, I’ve compiled the following list of CAD block and part libraries as well as related resources.

Online Block, Part and Model Library Websites

These are the types of sites you will want to look into first when searching for parts, models and blocks for a specific project or for your overall library. Most are loaded with free downloads in multiple formats. Some also include downloadable LISP routines as well. LISP, which stands for “list processor,” is a programming language that allows you to create small programs and macros that help extend and customize the functionality of your CAD software.

  • 3D ContentCentral—SOLIDWORKS-specific website with free service for locating, configuring, downloading and requesting 2D and 3D parts and assemblies, 2D blocks, library features and macros. The site offers an active community of nearly one-and-a-half million CAD users who share and download user-contributed and supplier-certified 2D and 3D parts and assemblies, 2D blocks, library features and macros.
  • 3DModelSpace—Website that helps engineers and CAD designers find 3D CAD models and CAD drawings of supplier parts, resulting in a library of over 750,000 CAD models. The site offers a standard parts library specifically geared for PTC Creo but also includes links to online supplier CAD catalogs with CAD models and parts available in additional formats such as STEP, IGES, Parasolid, SAT, 3D PDF and DXF.
Example of a download page for a 3DModelSpace supplier catalog part. (Image courtesy of 3DModelSpace.)

Example of a download page for a 3DModelSpace supplier catalog part. (Image courtesy of 3DModelSpace.)
  • 3D Warehouse—Google SketchUp–specific site for downloading 3D models and materials.
  • ARCAT—Geared for architects with a library of over 7,000 manufacturer’s specifications, CAD details, drawings, blocks, 3D models and building information modeling (BIM) objects, along with a directory of building products and manufacturers.
  • APLUS—AutoCAD architectural add-on with over 2,500 functions available as a $53-per-month subscription or via a full commercial license. The site also features a free downloadable library of over 27,000 blocks.
  • Autodesk Seek—Autodesk site providing high-quality BIM models and CAD drawings, including SketchUp content and product specifications.
  • BiblioCAD—CAD tools for architecture, design and construction with over 30,000 DWG, 3DS, MAX, DXF, PAT, LSP and PDF 3D files, among others, grouped into 36 categories.
  • CAD Blocks Free—Multi-CAD platform for professionals that has thousands of both free and fee-based downloadable 2D drawings, 3D models and parts in AutoCAD, Revit, 3ds Max and Sketchup formats.
  • CAD Corner—AutoCAD-specific website with free tutorials and a large selection of links. The site also offers AutoCAD blocks, details, LISP routines, text styles and hatch patterns.
  • CAD Forum—Offers free tips and tricks, blocks and discussion about AutoCAD, LT, Inventor, Revit, 3ds Max and other Autodesk products, utilities and add-ons.
  • Draftsperson.net—Free architectural 2D AutoCAD blocks, LISP routines tutorials and a user forum.
  • GrabCAD—Multi-CAD platform website offering nearly 1.2 million free 2D and 3D CAD blocks, parts and models. The site also offers CAD collaboration tools as well as other resources such as tutorials, webinars, case studies and articles.
3D PC ball valve file uploaded to GrabCAD and available for download. (Image courtesy of Jay Bhatt.)

3D PC ball valve file uploaded to GrabCAD and available for download. (Image courtesy of Jay Bhatt.)
  • RevitCity.com—Revit-specific website offering model-rendering galleries, forums and tutorials. The site lets users download models, patterns, templates and more.
  • TraceParts—Multi-CAD platform for designers offering over 100 million free CAD 3D models and parts from a variety of industries, all of which are available for download.
3D model of Tecnodin universal tubular lock with knob available for download. (Image courtesy of TraceParts.)

3D model of Tecnodin universal tubular lock with knob available for download. (Image courtesy of TraceParts.)
  • TurboSquid—Multi-CAD platform for professionals that has both free and paid 3D models and parts available for download, including cars, people, textures, architectural models and more.
Example of a free downloadable architectural model. (Image courtesy of TurboSquid.)

Example of a free downloadable architectural model. (Image courtesy of TurboSquid.)

Online CAD Stores

While most of the parts, blocks and models needed can probably be found for free on one of the sites mentioned above, don’t rule out the following sites, especially if you are in need of a validated model for a specific component. Validated models are certainly worth the project expense, especially when you want to avoid costly design errors derived from erroneous component information.

  • CADalog—CAD add-on superstore containing dozens of the most popular CAD add-ons, plug-ins and content collections.
  • CADdepot—Online CAD store featuring software, parts, part libraries, PDFs, tutorials, translators and viewers.

Manufacturer and Supplier Resources

This list includes some generic supplier sites as well as some industry-related sites our company commonly uses. There are industry-specific suppliers and sites for nearly every industry, all of which offer parts, blocks and models for download. Don’t underestimate these resources.

  • DE-STA-CO—Website offering downloadable parts for the workplace and automation industry, including clamps, grippers, indexers, slides, conveyors and robotic-tooling and remote-handling products.
  • Essentra Components—Website with downloadable parts for hardware, handles, clamps, tooling components, bearings and power transmission products.
  • McMaster-Carr—Website with downloadable parts used to maintain manufacturing plants and large commercial facilities worldwide. 
Steel-tapered roller bearing available for download in multiple formats. (Image courtesy of McMaster-Carr.)

Steel-tapered roller bearing available for download in multiple formats. (Image courtesy of McMaster-Carr.)
  • Prince Manufacturing Corporation—Website with downloadable parts for hydraulic components such as cylinders, mobile valves, gear pumps and motors.
  • ThomasNet—Website with downloadable parts for procurement professionals, engineers and plant and facility managers.


Additional Resources

Online CAD Publications

Although these sites may not have part libraries, they are a great resource for research and discussion. Their articles and forums can shed light on what might work best for your industry and get your search pointed in the right direction.

  • CADdigest—An online source for CAD, CAM, BIM and CAE articles.
  • Cadalyst—Online magazine offering news items, reviews, articles, tips and training.
  • ENGINEERING.com—Online destination for engineers of all disciplines. With free tools, games, jobs, email accounts and an extensive engineering library and directory.
  • TenLinks—Website that finds and organizes sites in all subjects of interest for technology professionals.

User Groups and Affiliations

Many CAD software companies have a community or user group associated with them that can help you when building your part library. Specific industries often have their own associations that can be great resources as well. For example, the American Institute of Steel Construction has structural steel shapes available for download. This has been a great resource for our steel-detailing division. Here are a few of those resources from my research—again, specific to our industry. Be sure to research the user groups and affiliations for the industries in which you are involved.

Value-Added Resellers

Don’t forget to look into your value-added resellers from which you buy your CAD software. Their job is to support you in your utilization of the software, and most are happy to provide input or suggestions on part libraries and other resources that fit your business.


The affiliations and resources document that I created for use within our company is organized by category. It’s also linked to the related content within the document, including locations on our network for user-created parts, CAD blocks and models. This helps our CAD users quickly and easily access information they need. I would recommend a similar setup when creating similar documentation for your organization. Although some of the resources I have listed are industry specific to our company, if you follow these guidelines and apply this to your own industry, you will be well on your way to building a toolset that helps your CAD users work more accurately and efficiently.

About the Author

Jeffrey Heimgartner has more than 20 years of experience in the computer-aided drafting and design field. He manages the Lincoln, Nebraska-based drafting and design firm, Advanced Technical Services. His main responsibilities include managing the CAD team, sales, scheduling and coordinating projects, drafting and design, as well as marketing and all IT functions.

Jeffrey earned his bachelor’s degree in Industrial Technology with an emphasis in Computer Aided Drafting and Design from Wayne State College in Wayne, Nebraska. He has a background in farming and construction and has authored many published industry-related articles.