8 Best Sites for Free 3D CAD Models & CAD Libraries

Primarily used by designers, engineers, draftsmen, and architects, CAD (computer-aided design) facilitates every step of the creative process: exploration of design ideas, specification-complete geometric dimensioning & tolerance (GD&T) drawings, and visualized concept renderings.

CAD libraries are what you would expect from a library: A treasure trove of 3D parts, from helical gears to anatomical hearts, and everything in between. In identifying the best available CAD libraries, a few key details were considered:

• Number of parts: How easy is it to find specific items to suit your needs?
• Navigation: Do the searches and filters work effectively? Does the layout facilitate the search for the right parts? Does a simple search return what’s expected, or do the results contain unrelated models?
• File formats: Which CAD platforms are supported? Are 3D printable formats available?
• Extras: Does the site offer 3D printing services, tutorials, prizes, apps, or further information in addition to the pure CAD models?

Based on these aspects, here are eight of the best CAD libraries available online today.

GrabCAD is advertised as the largest worldwide community of CAD users, boasting over 6.2 million members. The site itself has a good layout, with an easy-to-follow search format and drop-down menus to filter by category or by the software the model was created on.

• GrabCAD boasts a reasonable number of parts. Searching for the keyword “gear” returned nearly 2,000 results and “heart” returned nearly 800.
• The platform also covers a variety of file formats: STEP, IGES, Solidworks, Catia, SketchUp, Rendering, and 3D printable STL files amongst others.
• Searches produce mostly keyword-related parts. A couple of random items were thrown into the mix, but searching was generally quite effective. Filters are available for categories, including “3D printing”.
• Additional tutorials exist across a diverse field of topics. These include everything from optimizing part geometry to step-by-step guides on modeling with specific software. Design challenges are also available for community members.

TraceParts has a good number of users (currently 3.5 million) and also a massive number of part catalogs for various companies. The site is easy to navigate, with an obvious search bar on the homepage and a range of model categories that is clear and comprehensive.

• This library offers a significant number of official company-affiliated parts. Available for a wide range of applications, these files are easily downloaded. Searching for keyword “gear” returned 606,023 results.
• Apart from supporting an extensive range of file formats, also accommodated are different versions of some software (Catia v4 and v5) and 3D printable file types, including STL and OBJ.
• Searches are directly related to resulting parts. A large variety is displayed for the keyword “gear”, including bevel, helical, couplings, gearboxes, and DC gear motors.
• Helpful features include news on part catalogs and milestones, a blog comprising case studies, and newsletters on new products and 3D printing – nothing in the way of tutorials or prizes, though.

Thingiverse is a design community affiliated with MakerBot aimed at discovering, making, and sharing 3D printable models. Advertising itself as the largest such community, every model is licensed under a Creative Commons license, allowing anyone to use or alter any design.

• Thingiverse has a great number of parts to download across a large product range. Searching for “gear” returned 8,810 results, and “heart” returned 3,032 results, with further refinement possible through a series of filters by category and license type, among others.
• Files are purely for 3D printing.
• All parts within searches can be traced back to the original keyword or phrase.
• Bonus features include a challenges section with previously completed tasks listed as well as an education section and a list of apps to help you with your projects.
• There is a built-in option to order all models printed.

3D Content Central has just under 2 million users and involves both user-contributed and supplier-certified parts and assemblies. The search bar is immediately obvious with recently-added suppliers and top user content available from the homepage.

• 3D Content Central includes a large number of parts to download across a decent-sized product range. Searching for “gear” returned nearly 5,800 results.
• File formats include cross-software compatible types (such as IGES and STEP) as well as specific types for a large number of different platforms, including SolidWorks, Catia, AutoCAD, and Autodesk Inventor.
• All parts within searches are directly related to the original keyword or phrase. “Gear” has its own dedicated category within the overall model category list.
• While additional extras aren’t directly offered, a link to user support will take you directly to the affiliated software (SolidWorks), offering training, tutorials, blogs, podcasts, events, and webinars.

Part Community, with roughly 500,000 members, includes both 3D CAD supplier catalogs and user-contributed 3D models to cover the needs of both professionals and hobbyists. The site has an easy-to-follow layout with the two areas (amongst others) to make navigation a breeze.

• Through Part Comunity, you have access to a great number of parts to download. We couldn’t gather any numbers on keywords “gear” or “heart”, but across such a wide range of both manufacturers and community users, you’re guaranteed not to run out of things to search for and download any time soon!
• File formats include cross-software applicable types (such as IGES and STEP) as well as specific types for a large number of different platforms, including Solid Edge, SolidWorks, NX, Creo, Catia, and Autodesk Inventor.
• All parts found within the professional supplier searches are directly related to the original keyword or phrase. The user-contributed items threw the odd unrelated result (for example shackles coming up under the search for “gear”).
• Extras include a news section on members, technologies, and suppliers as well as a support area with a dedicated “Part Cloud 3D Modeling World Championship”. There are also some tips and tricks and FAQs on catalogs.

MyMiniFactory is a digital platform for guaranteed 3D printable models, whereby every single model is run through a software check and is then test printed by the community before it is published on the site. The search bar isn’t immediately obvious but, once used, opens up to a wide range of easily navigable categories through drop-down filters.

• The “gear” search returned 869 total results, and “heart” returned 861, which is reasonable.
• Models are meant for 3D printing.
• All parts within searches are directly related to the original keyword or phrase – no rogue results within the sample keywords.
• The platform has great optional extras, including design competitions, where $112,434 worth of prizes have been won so far across 137 competitions.

3D Export is primarily a marketplace to buy and sell 3D models as well as textures for use in computer graphics projects. It also contains a free area for 3D model downloads as well as being an easy-to-navigate site with well-segmented categories and an obvious albeit small search bar.

• A good amount of downloadable parts are available, with “gear” returning 906 items and “heart” returning 529 items.
• Supported file formats include IGES, STEP, Blend, STL, OBJ, SolidWorks, and AutoCAD, along with many others. It is worth noting the majority of formats do favor direct 3D printing applications.
• The majority of parts within searches are directly related to the original keyword or phrase.
• There are a wide range of tutorials on a variety of categories, from modeling to lighting to sculpting.
• Includes a “More” section with animations, blueprints, eBooks, and magazines.

Yeggi calls itself the search engine for 3D printable models, with over 2 million available. As can be expected, the search bar is clear and the options alongside allow for some fine filtering of results.

• Both “gear” and “heart” returned 1,919 models, linking results from some of the aforementioned sites, such as Thingiverse, MyMiniFactory, and 3D Export.
• File formats are primarily 3D printable, but with some open-source 3D CAD files, users are still able to find models they can download and edit.
• All parts within searches are directly related to the original keyword or phrase, with the search across multiple library sites seemingly filtering out any erroneous results.
• The section “3D Printing News” has videos, tutorials, and reviews.

The above list includes some of the most popular and widely-used CAD libraries available. That said, some are naturally suited to technical applications, with others being targetted towards hobbyists, so keep an eye out for sites relevant to your applications.

It is always recommended that, where possible, you download a model in the format your software natively uses. Downloading a SolidWorks model for SolidWorks rather than, say, a STEP or IGES file will allow you to easily edit the file to fit your specific needs.

As you can see, there are many sites out there which can help you find a wide variety of models. Whatever you decide to download, you certainly can’t go wrong with any of the CAD libraries above.

Feature image source: GrabCAD