3D CAD Design

From robots and hinges to gears and drill guides, here are the best sites to find 3D files for mechanical parts for your designs or to 3D print.

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While there is no shortage of CAD software tools available for free, not all of them cater to the specific needs of 3D printing enthusiasts. The ease of interaction with the 3D printing process is of utmost importance, as it allows for the creation of 3D models that can be readily converted into 3D print instructions.

This is usually achieved by saving the design in the commonly used STL or OBJ format. Another important aspect to consider is the printability of the model, especially when customizing or manufacturing parts. Some modeling platforms produce models that require adjustments before printing.

Lastly, it is important for the CAD and 3D modeling software to be user-friendly, as it should facilitate the physical production of objects through 3D printing. Having covered the essentials that make CAD software ideal for 3D printing, it’s time to explore the top free options currently available on the market

Blender

For many, Blender is the epitome of 3D computer graphics software. It’s considered the best not only because it’s open source and free but also due to its plethora of features, versatility, and professional use cases.

Examples include 3D modeling, texturing, rigging, skinning, smoke simulation, particle simulation, animation, rendering, and video editing. And those are really just a fraction of the things it offers.

Naturally, Blender is more than capable of producing models for 3D printing, but the learning curve is quite steep. Blender is considered to be a difficult tool to master, and the many features can make it both intimidating and confusing for those new to CAD.

Level: Advanced-professional OS: Windows, MacOS, Linux License type: Free to use

Blender is complex software that can handle 3D modeling for 3D printing (Source: Heavypoly via YouTube)

BricsCAD Shape

Born from the BricsSys platform of software, BricsCAD Shape is a completely free modeling and visualization program. It works in the DWG file format and supports direct imports from SketchUp. It can open only DXF, DWG, and DWT file types, which might limit the user, depending on the project.

The graphical user interface (GUI) is functional and easy to navigate with a standard toolbar and sidebar layout. Manipulation, albeit limited, is very responsive. It packs the necessary tools to create simple architectural and design models, as well as mechanical parts and assemblies.

It includes a visualization and rendering environment for previews, with a browsable 3D space to get some great snaps of what the final part will look like. Among the supported export formats are DAE, FBX, and STL.

Level: Beginner-intermediate
OS: Windows, MacOS, Linux
License type: Free

BricsCAD Shape is well-suited to designing architectural models (Source: BricsCAD)

DesignSpark Mechanical

Here’s a more advanced CAD option: DesignSpark Mechanical. It relies on parametric modeling methods and offers tools equivalent to other popular CAD solutions on the market.

The interface was deliberately designed to resemble AutoCAD, presenting itself as a suitable and free alternative.

DesignSpark Mechanical is free to download, but additional functionality, like working with STEP and IGES formats, requires paid add-ons. Fortunately, core functionalities include exporting models in STL format, so the free version is perfectly adequate for 3D printing applications.

Level: Intermediate
OS: Windows
License type: Free to use with paid add-ons

DesignSpark Mechanical is a great option for those familiar with CAD software (Source: RS DesignSpark via YouTube)

FreeCAD

FreeCAD is a free, open-source parametric CAD modeler. It’s a great entry point for designers and mechanical engineers that are new to the 3D modeling world.

Parametric modeling refers to the way 3D models can be entirely modified by only adjusting individual elements and constraints. It’s the technique most used in professional CAD software for precise and accurate design work.

The GUI may not look as polished as other programs on this list, but FreeCAD is definitely a tool for serious design. Finally, it can export a wide array of formats, including STL and OBJ for 3D printing and other formats suitable for model sharing like STEP, IGES, and DWG.

Level: Intermediate-expert
OS: Windows, MacOS, Linux
License type: Free to use

FreeCAD is a more complex tool ideal for precise design (Source: R-Frank via Wikimedia)

Fusion 360

If you’re looking for full-blown CAD software that’s relatively easy to use and allows you to drill down to professional depths, Fusion 360 is the right choice for you. It allows for parametric, free-form, surface, and mesh modeling but can still export STLs for 3D printing.

Fusion 360 is one of the most popular CAD options for hobbyists, bringing tools and features comparable to high-end solutions like SolidWorks.

While the software is paid, Autodesk offers a limited personal-use license for non-commercial projects for free. This license no longer offers the full suite of features, but it does include the same design and modeling tools as paid versions.

Level: Intermediate-professional
OS: Windows, MacOS
License type: Free for non-commercial uses

Fusion 360's free license is as close as any free CAD software gets to professional tools (Source: Autodesk)

Meshmixer

Meshmixer is a free 3D program by Autodesk that’s focused on 3D printing. For starters, it works exclusively with polygon mesh 3D files in formats like STL and OBJ.

It’s also a popular tool for analyzing, editing, and repairing files from online model repositories like Thingiverse and MyMiniFactory. In addition, it can generate support structures for 3D printing both manually and automatically.

Making models from scratch is also possible with Meshmixer, which uses a 3D modeling technique known as 3D sculpting. This method is most suitable for creating organic shapes like characters and faces, as opposed to many of the more CAD-oriented solutions in this list.

Level: Intermediate
OS: Windows, MacOS
License type: Free to use

Meshmixer is a 3D sculpting program focused solely on modeling for 3D printing (Source: Peopoly)

Onshape Free

Onshape is a deep and versatile CAD program that goes beyond designing 3D models. The self-proclaimed “all-in-one product development platform” allows for parametric modeling, team collaboration, and data management, but its forte is in technical and spare parts.

This is one of the few professional platforms that’s entirely web-based. Onshape offers an interesting deal for hobbyists and makers: If you’re willing to freely share your designs over a Creative Commons license, the software is free (with some limitations). However, if you want all the shiny new features while keeping your designs private, you’ll need the full paid version.

Level: Intermediate-professional
OS: N/A (browser-based)
License type: Free, but designs created are available for everyone to use

Onshape is a CAD tool that's exclusively browser-based with options for free licenses (Source: Onshape)

SelfCAD

SelfCAD is a full-fledged environment that supports CAD model design, free-form sculpting, rendering, animation, and even 3D slicing. The entire package can be accessed either online via a web interface or offline by installing it locally.

Newcomers and occasional designers will appreciate the straightforward approach to modeling, and the included interactive tutorials are a great way to get started.

The interface is slim but functional. The GUI won’t confuse the user with too many tools to choose from. It also features a slicing engine that supports a decent range of printers, with the option to customize the profiles. It has a free license alongside a paid one packed with a few more tools.

SelfCAD's UI is easy to navigate and resembles Fusion 360 (Source: SelfCAD)

3D Slash

3D Slash is billed as an easy-to-use 3D modeling tool that’s especially friendly for non-designers and children. With a basic set of tools, users can model shapes much like a stonecutter: adding and removing cubes of a user-defined size.

More advanced features allow users to model with more precision. Images can be used either to sculpt shapes or as a stencil to engrave models. Multi-part models can be modeled with different colors, then exported by color. And this is only a smidgen of the many features offered by a modeling program that’s so light it can run on a Raspberry Pi.

3D Slash is offered in both free and paid versions. The free version is limited to the web application, a reduced color palette, and queued exports. All of the subscription plans offer modeling in a higher resolution, a full-color palette, immediate exports, and functional use of the 3D Slash app.

Level: Beginner
OS: Windows, MacOS, Linux, Raspberry Pi OS (or browser-based tool)
License type: Creative Common License BY–NC–SA for users of the free version and premium subscribers; commercial use for professional subscribers

As easy as playing a game (Source: 3D Slash)

Tinkercad

Tinkercad is one of the most popular educational 3D modeling tools. Its interface and featured tools are friendly and easy to use, making the 3D design process fun for kids, hobbyists, educators, and above all, beginners.

In regards to 3D printing, users can export designed objects in the STL format. Another great feature of Tinkercad is that it’s completely browser-based, so there are no compatibility issues and minimal system requirements.

The platform offers plenty of learning resources and projects, and it’s especially useful for those learning or even teaching 3D modeling. Tinkercad also hosts a user gallery where 3D models from other users can be viewed and even copied for further customization.

Level: Beginner
OS: N/A (browser-based)
License type: Free to use

Tinkercad is simple to use but capable of sophisticated 3D design work (Source: Tinkercad via Moose3D)