View CAD Files Online — Free STL & OBJ Viewer

The "I Don't Have That Software" Problem

Engineering workflows produce 3D files constantly. A mechanical engineer exports an STL from SolidWorks for 3D printing. A product designer sends an OBJ from Fusion 360 for a client review. A manufacturing team receives step files converted to mesh formats for inspection. In every case, the person receiving the file may not have the originating CAD software installed.

This is a surprisingly common bottleneck. SolidWorks licenses cost thousands of dollars per year. Fusion 360 requires an Autodesk account and a desktop install. Even free options like FreeCAD take time to download, install, and configure. When all you need to do is look at a part — confirm the geometry, check the orientation, verify it's the right revision — installing a full CAD suite is absurd overkill.

The practical result is that engineers and project managers waste time on file logistics. They email files back and forth, ask the sender for screenshots, or install viewers they'll use once. This is friction that shouldn't exist in 2026, and for the most common mesh formats, it doesn't have to.

What GeometryViewer Opens

GeometryViewer is a browser-based 3D viewer that handles the mesh formats most commonly exported from CAD software:

• STL (Stereolithography): The universal exchange format for 3D printing and rapid prototyping. Every CAD tool can export STL. Both ASCII and binary variants are supported.
• OBJ (Wavefront): A widely supported mesh format that can include material definitions and texture coordinates. Common as an export target from Fusion 360, Rhino, Blender, and many others.
• GLB/glTF: The modern web-standard 3D format. Increasingly supported as an export option in CAD tools, especially those targeting web visualization or AR/VR workflows.
• 3MF: The newer 3D printing format designed to replace STL. Supports color, materials, and metadata. GeometryViewer handles the geometry and color data.

To view a file, drag and drop it onto the GeometryViewer page. The model appears immediately in an interactive 3D viewport. You can orbit, zoom, and pan using mouse or touch controls. There's no upload queue, no processing delay, and no account requirement. The file is processed client-side in your browser — it never leaves your machine unless you choose to share it.

Common CAD-to-Viewer Workflows

SolidWorks to STL

SolidWorks' native format (.sldprt, .sldasm) is proprietary and can only be opened in SolidWorks or its free viewer (eDrawings). However, every SolidWorks user can export to STL via File > Save As > STL. The export dialog lets you control mesh resolution — for visual inspection, the "Fine" preset is usually sufficient. For 3D printing, use the custom settings to ensure adequate triangle density on curved surfaces.

Once exported, the STL file can be opened in GeometryViewer by anyone, regardless of whether they have SolidWorks. This makes STL the practical "lingua franca" for sharing SolidWorks geometry with external collaborators.

Fusion 360 to OBJ or STL

Fusion 360 supports exporting to both STL and OBJ. For parts with color or material information you want to preserve, OBJ with an accompanying MTL file is the better choice. For simple geometry inspection, STL is simpler (single file, no dependencies). Export via File > Export, selecting the appropriate mesh format. Fusion 360 also supports direct STL export from the "Make" (3D print) workflow.

FreeCAD to STL

FreeCAD is the most popular open-source parametric CAD tool, and many hobbyists, students, and small businesses use it. Export to STL via File > Export, selecting the STL Mesh format. FreeCAD's meshing can sometimes produce low-density tessellations on curved surfaces — if the model looks faceted in GeometryViewer, re-export with a finer mesh setting (Edit > Preferences > Part Design > Shape View, reduce "Maximum deviation").

Rhino to OBJ

Rhino (Rhinoceros) is heavily used in industrial design, jewelry, and architecture. Its native .3dm format is proprietary, but OBJ export is built in and well-tested. Use File > Export Selected > OBJ. Rhino's OBJ exporter preserves materials and can include texture maps. For best results in GeometryViewer, export with NURBS-to-mesh conversion at a reasonable polygon density — Rhino's default settings are usually fine for visualization purposes.

What GeometryViewer Doesn't Do (and When to Use Something Else)

It's important to be clear about limitations, because choosing the wrong tool wastes more time than using no tool at all.

No native CAD format support. GeometryViewer cannot open STEP (.stp), IGES (.igs), SolidWorks (.sldprt), or Inventor (.ipt) files directly. These are parametric formats that contain construction history, constraints, and feature trees — information that a mesh viewer cannot interpret. You need to export to a mesh format (STL, OBJ, GLB) from the originating CAD software first.

If you receive a STEP or IGES file and don't have CAD software, your best options are: Autodesk Viewer (free, web-based, handles STEP natively), FreeCAD (free, desktop, opens STEP and IGES), or eDrawings (free viewer from SolidWorks, handles many native formats).

No measurement tools. GeometryViewer is a visual inspection tool. You can see the geometry and rotate it, but you cannot measure distances, angles, or wall thicknesses. If dimensional verification is your goal, you need a tool with measurement capabilities — Autodesk Viewer, FreeCAD, or even a slicer like PrusaSlicer (which shows dimensions for STL files).

No section views or exploded views. CAD-oriented viewers often let you cut a section plane through the model to inspect internal geometry, or explode assemblies to see individual components. GeometryViewer renders the model as-is, showing only external surfaces. For internal inspection, you'd need to modify the export (e.g., hide components in SolidWorks before exporting) or use a CAD-capable viewer.

When to Use GeometryViewer vs. Autodesk Viewer

This is the most common comparison engineers ask about, so it's worth addressing directly.

Use GeometryViewer when: You have a mesh file (STL, OBJ, GLB) and you just need to look at it. The model loads instantly, the controls are intuitive, and there's no account requirement. It's also the better choice when you want to share the model with someone non-technical — the shareable link opens in a clean, distraction-free viewer.

Use Autodesk Viewer when: You have a native CAD format (STEP, IGES, DWG, Revit, Inventor, SolidWorks) and don't want to convert it. Autodesk Viewer handles 70+ file formats natively. It also offers measurement tools, section views, and model tree navigation. The trade-offs are that it requires an Autodesk account, the upload processing takes longer (the server converts the file), and the interface is more complex.

In practice, many engineers use both: GeometryViewer for quick mesh inspection and sharing, and Autodesk Viewer for detailed analysis of native CAD formats. They solve different problems and complement each other well.

Tips for Better Results

• Use binary STL, not ASCII. Binary STL files are 5-10x smaller than ASCII equivalents with identical geometry. Most CAD tools default to binary, but some (especially older versions) may default to ASCII. Check the export settings.
• Increase mesh density for curved parts. CAD tools tessellate NURBS surfaces into triangles during STL/OBJ export. If your part has curves that look faceted in the viewer, re-export with a finer mesh resolution.
• Combine multi-body parts before export. If your CAD assembly has many separate bodies, some export workflows create separate mesh files for each body. Combine them into a single STL/OBJ for easier viewing.
• Check units. STL files don't store unit information. A part modeled in inches will appear tiny if the viewer assumes millimeters, and vice versa. GeometryViewer auto-scales to fit the viewport, so the model will always be visible, but be aware of this when interpreting scale.