Step File Viewer

3D Viewer online is an online STEP viewer that allows you to easily visualise STEP 3D files directly on the browser, letting you perform all the actions that you would normally do to inspect a STEP 3D model such as rotate, zoom in/out, measure, section and more advanced actions such as taking high resolution screenshots, create annotations with markups and comments and embed your 3D model in external websites and applications.


  • What is a STEP file?
  • How to use the STEP viewer
  • Difference between STL and STEP
  • Where to find free STEP files?

What is a STEP file?

Step files represent 3D objects made with CAD and show their structure and properties.

The STEP file format is a widely used standardized format in product manufacturing, also known as ISO 10303. This format is considered the best for exchanging data between CAD systems such as Solidworks, CATIA, and AutoCAD.

There are many advantages in using STEP Files in engineering and manufacturing:

  1. Interoperability:

    One of the primary advantages of STEP files is their ability to facilitate interoperability between various CAD systems. Different software applications may have proprietary file formats, making it challenging to share models seamlessly. STEP serves as a bridge, enabling designers and engineers to collaborate across different platforms.
  2. Data Preservation:

    STEP files store not only the geometric information of a 3D model but also its metadata, such as materials, assembly structure, and other product-related data. This comprehensive data preservation ensures that critical information is not lost during file conversion or transfer.
  3. Standardization:

    As an ISO standard, STEP provides a consistent and standardized way to represent product data. This ensures that data interpretation is uniform across different software applications, reducing the chances of errors and miscommunications in the design and manufacturing process.

Understanding the Structure of STEP Files:

STEP files are organized into modules, each serving a specific purpose. The two primary modules are:

  1. Geometry (B-Rep): The geometry module represents the 3D shape of the model using B-Rep (Boundary Representation). B-Rep defines the surfaces, curves, and topology of the 3D object, allowing for an accurate representation of its form.
  2. Product and Manufacturing Information (PMI)

    Complementing the geometry module is the Product and Manufacturing Information (PMI) module. PMI encapsulates data related to the product beyond its visual representation. This includes information about the assembly structure, materials, tolerances, annotations, and other details crucial for manufacturing and product lifecycle management.
    • Assembly Structure:

      The assembly structure within the PMI module outlines how individual components come together to form the complete product. This hierarchical representation is vital for understanding the relationships between different parts and their positioning within the overall assembly.
    • Materials and Textures:

      STEP files can store information about the materials used in the design, allowing for a more realistic representation of the model. This is especially important in industries where material properties play a significant role in the product’s functionality.
    • Tolerances and Annotations:

      PMI includes details about tolerances, annotations, and other manufacturing specifications. These annotations provide additional information about the design intent, helping manufacturers and engineers understand critical aspects of the product.

While STEP files offer numerous advantages, some challenges should be considered when working with them:

  1. File Size:

    Depending on the complexity of the model and the amount of metadata included, STEP files can become large. This may pose challenges in terms of storage, file transfer, and system performance. For the best performance with the STEP Viewer, we suggest to reduce the number of parts whenever possible.
  2. Loss of Advanced Features:

    Some CAD systems have advanced features and functionalities that may not be fully supported by the STEP format. Users should be aware that certain proprietary attributes might be lost during the conversion process. To check if all the desired features have been exported and therefore can be correctly visualised in the STEP Viewer, try to open the exported STEP file with multiple CAD packages. 

STEP files are used in multiple applications and industries:

  1. Automotive Design and Manufacturing:

    In the automotive industry, where collaboration among multiple stakeholders is essential, STEP files streamline the exchange of design data. From the intricate geometry of vehicle components to manufacturing specifications, STEP facilitates a seamless workflow.
  2. Aerospace Engineering:

    Aerospace projects involve complex assemblies with stringent tolerances. STEP files are instrumental in conveying not only the geometric intricacies of aircraft components but also the precise manufacturing information required for aerospace engineering.
  3. Consumer Electronics:

    The consumer electronics industry relies on rapid innovation and collaboration. STEP files enable the exchange of detailed 3D models, ensuring that designers, engineers, and manufacturers can work together effectively to bring cutting-edge products to market.

Start using the online STEP viewer now by registering a FREE account.

How to use the STEP viewer

Step file

Other than just viewing a 3D design, with the online STEP viewer you will be able to do the following:

  • View/Inspect a STEP file

  • Hide/Show a single part of the project

  • Create markups and comments directly on the 3D model

  • Share the file with your collaborators

  • Take a screenshot of the 3D model

  • Download the STEP file

  • Measure the graphic (distance between points, overall size, diameter)

  • Section

  • Explode the 3d object (if made of multiple parts)

  • Hide/Show contour lines

  • View the file viewer in full screen

  • Embed the 3D model in external websites and applications

  • View the online STEP viewer from tablets and mobile devices

  • Select a predefined View (Top, Right, etc..)

All these functions are available on the online STEP viewer toolbar located on the top left part of the screen and do not require any previous knowledge of a 3D software.

Most popular and useful actions you can perform on the STEP viewer

Hide/Show parts of the STEP 3D model

The Hide/Show function of the online STEP viewer lets you hide or show any part of the STEP 3D model. You can select the part to hide/show from the part list displayed on the left side of the window, or directly from the 3D by clicking on the Select from 3D arrow icon located on the top section of the part list. You can use the Select from 3D feature to find the part name. This feature allows you to click on a section of the STEP 3D model. If necessary, you can then hide the part. You can also hide or show all the parts at the same time by clicking on Hide/Show all.

hide/show parts

Measure the STEP 3D model

The measuring functions of the online STEP viewer allow you to measure the distance between two points, the overall size of the 3D model and the diameter of a circular feature. Measuring and verifying the thickness of a wall for instance, becomes extremely important when the 3D design has to be manufactured. In the picture below an example of a measurement between two points is presented.  

step distance between two points

You can change the dimension unit of your measurement result by using the top down menu located at the right of the measurement value. The default unit is mm but it can be switched to cm, m, ft or in depending on your preference.

Section the STEP 3D model

The online STEP viewer’s sectioning function allows you to explore the inside of the STEP model using various sectioning planes.
The X section plane for instance, is the plane normal to the X direction (also referred as Y-Z plane). The same applies for the Y and Z section planes. By moving the slider located on the top right part of the page, the sectioning plane will move accordingly cutting the STEP 3D model along the indicated direction.

step section

Explode the STEP 3D model

The Explode function of the online STEP viewer lets you create an exploded view of the STEP file. You can explode the 3D model more or less according to your needs, to better understand how all the parts are assembled together. This function is extremely useful to inspect complex technical models. The exploded view starts from the 3D model geometric centre and it is projected outward in all directions.

step exploded

Create markups and comments directly on the STEP 3D model

One of the most powerful features of the STEP Viewer, are markups and comments. The markups feature gives you the possibility to create markups by drawing and writing annotations directly on the step 3D model, for your own use or to better share your thoughts with your customers and collaborators.

The markups let you also easily highlight possible design issues on the step 3D model which might cause problems during production, saving therefore time and money compared to fixing the same issues at a much later production stage.

Markups step

The commenting feature allows you to create comments about the step 3D model, which might include markups as well if necessary. Posting or replying to comments is as easy as posting on any social platform. You also have the possibility to attach documentation to your post, such as material datasheets, simulation results or international standards. All your communication will be connected to the 3D model, making it easier for the people involved in your project to access and use it.

Embed the STEP 3D model directly on your website, CMS or app

The Embedding function of the online STEP viewer lets you embed the step 3D model directly in your website, CMS or app by using an iFrame code, similarly to what YouTube does for videos. This can add more 3D viewing capabilities to your platform, with engaging content.

Iframe dimension

Take a high resolution screenshot of the 3D model

The screenshot function of the online STEP viewer allows you to instantly download a high resolution picture of what you see on the screen. This feature is particularly useful when you need to include realistic renderings of your STEP file on your website or marketing material. To achieve the best realism with effects such as lights and reflections, you can easily edit the 3D settings of that 3D model (check out how to change the scene settings).

Start using the online STEP viewer now by registering a FREE account.

Difference between STL and STEP

Unlike a STL file, the STEP file does not include a list of vertices and facets, but a full geometric definition which includes dimensioning, tolerancing, analysis and additional information specific to various industries such as automotive, aerospace, building construction, ship, oil and gas, process plants and much more.

A list of the major differences is presented here below:

Information Depth:

  1. STEP: Emphasizes comprehensive product information, including geometry, materials, and manufacturing details.
  2. STL: Primarily focuses on surface geometry, providing a mesh representation for visualization and physical realization.


  1. STEP: Promotes interoperability between different CAD systems, facilitating collaboration.
  2. STL: Primarily used for specific applications like 3D printing, with less emphasis on interoperability across diverse CAD platforms.

Use Cases:

  1. STEP: Suited for industries requiring detailed product information and collaborative design efforts.
  2. STL: Ideal for rapid prototyping, 3D printing, and applications where precise surface geometry is paramount.

Where can you find free STEP files?


  1. Website: GrabCAD
  2. Description: GrabCAD is a community platform for engineers and designers. It hosts a vast library of CAD models, including free STEP files. Users can contribute and share their designs with the community.

2. 3D ContentCentral:

  1. Website: 3D ContentCentral
  2. Description: 3D ContentCentral is an online resource for 3D models provided by suppliers and manufacturers. It offers a wide range of CAD models in various formats, including STEP.

3. TraceParts:

  1. Website: TraceParts
  2. Description: TraceParts is a digital engineering platform that provides access to a large collection of CAD models. It includes free 3D models in STEP format from various manufacturers.

4. 3DFindit:

  1. Website: 3DFindit
  2. Description: 3DFindit is an online repository of 3D models provided by suppliers and manufacturers. It offers a wide range of CAD models in various formats, including STEP.

5. 3DModelSpace:

  • Website: 3DModelSpace
  • Description: 3DModelSpace provides a platform for sharing and downloading 3D models. It includes various formats, and you can find free STEP files among the available models.

Start using the online STEP viewer now by registering a FREE account.