Free online IGES file viewer: how to open and inspect a .igs file in the browser
A customer sends you a part as a .igs file and your laptop has no CAD installed. You can download a multi-gigabyte trial of a desktop package, wait an hour, and burn a licence seat — or you can drop the file into a browser tab and have it on screen in under a minute. An online IGES file viewer does exactly that: it reads the geometry, draws the 3D model, and lets you rotate, zoom and measure without an install.
This guide covers what an IGES file actually holds, how to view a .igs or .iges file online, where IGES differs from STEP, and how to take the model from "just looking" to a real quote and inspection plan.
What is an IGES file?
IGES (Initial Graphics Exchange Specification) is one of the oldest neutral CAD exchange formats, defined under the US standard ANSI/USPRO/IGES 5.3. The file extension is usually .igs or .iges. Like STEP, it is a vendor-neutral format, so a part exported from CATIA, NX, Creo or SolidWorks can be opened by anyone with a compliant viewer — no native licence required.
The catch is what IGES carries. IGES is fundamentally a surface and wireframe format. It describes curves, trimmed surfaces and, in many exports, a single lumped body. It usually does not carry a clean assembly hierarchy or rich product metadata. That makes IGES excellent for moving raw geometry between systems and weaker for anything that needs structure, such as a multi-line bill of materials.
How to view an IGES file online — step by step
Step 1: Open the viewer
Go to cadnexa.com, sign in with Google, and open the 3D Viewer. There is nothing to install and no plugin to enable — it runs in any modern browser on Windows, Mac, Linux or a Chromebook.
Step 2: Drag your .igs or .iges file in
Drag the file onto the viewer window. CadNexa reads the IGES surfaces and renders the solid in the browser. The file stays on your machine — it is parsed locally rather than uploaded to a server, which matters when the drawing is under NDA. The viewer also opens .step and .stp files, so a mixed folder of supplier data all goes through one tool.
Step 3: Rotate, zoom and measure
Use the mouse to orbit, pan and zoom. The measurement tools let you check a distance, a diameter or an angle straight off the model — useful for a fast sanity check against the 2D drawing before you commit to a quote. An exploded view helps separate stacked bodies, though remember that many IGES exports arrive as one body, so the explode may show less structure than the same part in STEP.
Step 4: Read the geometry and estimate weight
From the solid volume the viewer estimates mass once you assign a material — mild steel, aluminium 6061, SS 304 or brass. That gives you a first-pass raw-stock weight for costing. For Indian shops, local material rates turn that weight into a quick material-cost figure.
Open your next .igs file in the browser — free
View, rotate and measure IGES and STEP models in minutes. No CAD licence, no install, file stays on your machine.
Open the 3D Viewer — Free →IGES vs STEP: which format should you ask for?
| Aspect | IGES (.igs) | STEP (.stp / .step) |
|---|---|---|
| Standard | ANSI IGES 5.3 | ISO 10303 (AP242 / AP214) |
| Data type | Surfaces & wireframe | Solid (B-rep) with structure |
| Assembly tree | Often flattened to one body | Preserved — good for BOM |
| Metadata (PMI) | Minimal | Supports tolerances, attributes |
| Best use | Quick geometry exchange | Manufacturing, BOM, inspection |
IGES is not "worse" — it is older and simpler. For pure shape transfer it is reliable and widely accepted. But if your next step is to extract a bill of materials, STEP wins because the assembly structure survives the export. If you have a STEP version of the same part, prefer it for the BOM export workflow; keep the IGES for quick viewing and measurement.
Common problems when opening IGES files
- The model shows as one lumped body. This is normal for many IGES exports — the assembly tree was flattened. If you need separate parts, request STEP.
- Surfaces look open or have gaps. IGES stores trimmed surfaces, and a poor export can leave small gaps at the edges. The shape still views fine for inspection reference; for downstream machining, ask for a healed STEP solid.
- No tolerances or notes. IGES rarely carries PMI. The manufacturing definition still lives on the 2D drawing — the model is the shape, not the spec.
- Wrong scale or units. Confirm the units flag (mm vs inch) against the drawing title block before you measure anything off the model.
From viewing to inspection: the next step
Seeing the model is step one. The 2D drawing that came with the IGES file carries the dimensions and tolerances you actually have to inspect. CadNexa's auto-ballooning reads a PDF drawing with Smart Detect and Box+Balloon OCR, numbers every dimension, and builds an inspection sheet you can export to CSV. You can start that from the auto-balloon tool, and the full first-article workflow is covered in the learning center. If your supplier data is mostly STEP assemblies, the online STEP file viewer guide covers the BOM side in more depth.
Stop installing CAD just to look at one part
Open IGES and STEP files in the browser, measure them, and move straight into ballooning and inspection.
Try the IGES Viewer — Free →Frequently asked questions
Can I open an IGES file without CAD software?
Yes. CadNexa's browser-based 3D Viewer opens .igs and .iges files directly — no desktop CAD, no plugin, no install. It runs on Windows, Mac, Linux and Chromebook, and the file stays on your computer rather than uploading to a server.
Is the IGES viewer free?
The free tier lets you open and measure IGES and STEP files in the browser. Paid plans start at ₹399/month for teams that need heavier export volume, but viewing a part costs nothing to start.
What is the difference between IGES and STEP?
IGES is an older surface-based format that often flattens an assembly into a single body. STEP (ISO 10303) stores a solid model with the assembly hierarchy preserved, which is why STEP is better when you need a bill of materials or inspection data. For pure geometry viewing, both work.
Why does my IGES file open as a single part?
Many IGES exports do not preserve the assembly tree, so a multi-part assembly arrives as one lumped body. The shape is correct, but there is no structure to expand. Request a STEP file if you need the individual components and quantities.
Can I measure dimensions on an IGES model?
Yes. The viewer's measurement tools let you check distances, diameters and angles directly on the 3D model. Confirm the file units (mm or inch) against the drawing title block first, since IGES exports can carry either.