How to Share CAD Files for Review: Methods, Tools & Best Practices

Sharing CAD files for review used to mean exporting, compressing, and hoping the person on the other end could open what you sent. Today, engineering teams have far better options, and choosing the right one can meaningfully speed up your design cycles.

Whether you're sharing internally with cross-functional stakeholders, or externally with suppliers and contract manufacturers, the method you use affects everything: how fast you get feedback, how secure your IP is, and whether the feedback you receive is ownable and actionable. Here's a breakdown of your options, when to use each, and what good CAD sharing for review actually looks like.

The short answer: The most effective way to share CAD files for review is through a collaborative, browser-based design engagement system that doesn't require reviewers to have CAD software installed. It keeps your files secure, feedback in context, and your review process moving. The rest of this article explains why, and what to consider along the way.

Neutral vs. Native CAD Formats

If you're sharing with a partner on a different CAD platform, or a stakeholder who has no CAD software at all, your format choice determines whether they can open it, view it accurately, and give you feedback that's actually useful.

CAD files exist in two primary formats: neutral and native. Designers can use neutral file formats in any software, while native files contain information software designers optimized for their platform. The list of file types is not comprehensive, but it reflects common file types used in modern engineering design and manufacturing.

Neutral File Types

Engineering teams can use these file types to communicate components in a customer assembly or convey design features to a contract manufacturer who would fabricate the part. There are two principal neutral CAD file types: IGES and STEP.

• IGES files (.igs, .ige, .iges) convey surface models and can include gaps, misaligned orientations, or missing surfaces.
• ‍STEP files (.stp, .step, .stpz, .ste, .p21) are neutral file types used for solid 3D models. STEP is a newer format and is popular due to its improved accuracy over IGES.

Although these file types can work with most software, the conversion from native to neutral can introduce errors in the file. As a result, the absolute dimensions and features of STEP and IGES files may not translate precisely as the native file specified.

Native File Types

Native CAD files often contain more information than their neutral counterparts. As a result, they are most accurate when used in their intended software. However, while some file types may work in different environments, the accuracy in translating one file type to another software is not guaranteed.

2D File Types

• Drawing files (.dwg) are the digital format of a 2D component drawing. While designers can generate .dwg files independently, a standard process is creating the 3D component model and converting the part to a drawing using the software. Drawings can be of individual components with detailed data or assemblies containing a bill of material to document part quantities in a table within the file.
• ‍Drawing interchange format (.dxf) files interface with machinery to make piece parts. These applications include CNC machining, laser cutting, and waterjet cutting.

3D File Types

• Part files (.prt) translate an individual component or piece-part of an assembly. They contain specific information like surfaces, dimensions, lines, and descriptions.
• Assembly files (.asm) group individual .prt files together. They document the relationship of how the components fit together, the quantities of each, notes, and dimensional data.

Best CAD File Types for Sharing

3D Model and Part Files

It is essential to consider the application and reason for sharing a CAD file to select the best type. Detailed applications should use the file type optimized for them, such as PRT for Pro-E vs. SLDPRT for Solidworks. Machine applications often use DXF files, while CAE uses ASM to incorporate intricate design details required for analysis.

The most robust file type for sharing is the STEP file format. It incorporates 3D geometry and communicates with nearly every CAD or CAE software program. STEP files are a manageable size relative to their native counterparts and can up- or download without heavy transmission times. However, as mentioned above, STEP does carry the risk of slight translation errors when converting a native file.

If translation errors are a concern, one way around them is to use a platform that reads native files directly. CoLab supports 30+ file formats — including native CAD from SolidWorks, Creo, CATIA, NX, Solid Edge, and Inventor — and automatically converts them to a web-viewable format without requiring the reviewer to have the originating CAD software installed. No STEP export, no conversion risk.

2D Drawing Files

Collecting and transferring the drawing files from a CAD system to the prototype or production manufacturer is critical in translating a design concept into a physical part. The best practice is to store these files in a designated cloud-based directory for security and revision control. When you are ready to pull the drawing files and share them, there are a few things to consider:

• Does the drawing file need to be fully searchable?
• Is file size a limitation?
• Is the quantity of drawing files in an assembly large enough to warrant grouping them with software?

PDFs allow fully searchable text but take up more space with the added information. As a result, many companies opt for TIFF files, which act like wallpaper for images and are not fully searchable. Another advantage PDFs offer is the ease of combining into a binder file for easy transmission, vs. the one-by-one approach required with TIFF.

CAD File Sharing vs. CAD Collaboration

File sharing is critical when making design decisions, but collaboration doesn’t stop there. To select a supplier, review a drawing, or run a cost down workshop, engineers also need to discuss and track issues. There’s a big difference between file sharing and collaboration.

Using the example of a file created in AutoCAD, one of the first mainstream CAD programs, project teams will logically ask: can you collaborate on AutoCAD software itself? Since 2019, AutoCAD has allowed users to create shared views. This method of AutoCAD collaboration allows the recipient of a file to open it and create markups from within the AutoCAD web app. Then, the creator of the file can view that markup in their AutoCAD session.

Each CAD provider takes a slightly different approach to collaboration. For example, Creo users can create markups using PTC’s Creo View applications. Each vendor’s collaboration tools will typically accept their own native CAD files or a neutral format like STEP.

The limitation with vendor-specific tools is that they work best when everyone is on the same platform, which isn't how most supply chains are structured. The moment you bring in a supplier running a different CAD system, or a manufacturing engineer who doesn't have a CAD seat at all, those workflows break down.

CoLab is built for that reality. Reviewers open designs directly in a browser — no software installs, no file downloads or conversions. Feedback is pinned directly to model geometry with saved view states, so there's no ambiguity about what a comment refers to. Every piece of feedback is automatically tracked as a structured issue with an owner and status, so nothing falls through the cracks between the review and the next revision.

For external sharing, CoLab lets you control exactly what each supplier can see, comment on, or download, and you can revoke access when the review is done. It's the difference between sending a file and actually controlling where it goes.

For teams working inside a PLM, CoLab integrates directly with Windchill, Teamcenter, and 3DEXPERIENCE. Files push from PLM to a CoLab workspace without manual exports, revision data stays synced, and reviewers always know they're looking at the right version.

The Best Way to Share CAD Files for Review

The days of exporting, compressing, and hoping for the best are behind us. Engineering teams now have purpose-built options that match how modern product development actually works, across time zones, supply chains, and CAD platforms.

The right approach depends on your context: who you're sharing with, what tools they have, and how much control you need over your IP. But for most teams running real design reviews, internal or external, a browser-based platform that keeps files secure, feedback in context, and versions tracked is where the efficiency gains actually show up.

Want to see how engineering teams share and review CAD without the back-and-forth? Get a custom demo from a fellow engineer.

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