Free online STEP viewer
Open STEP and STP files without sending them away.
Caddis is a local-first browser viewer for STEP and STP models. Use it to inspect 3D geometry alongside your drawing-review workflow, without making an upload the default.
No account required for local viewing. Files stay on your device unless you opt into Cloud.What is a STEP file?
STEP (often saved as .step or .stp) is a neutral 3D CAD exchange format used to move product and engineering models between systems.
How to get started
- Open the Caddis web viewer.
- Choose a STEP or STP file from your device.
- Inspect the model and continue your review locally.
Built for practical review
- Open STEP and STP models in the browser
- Local-first processing
- One review workspace for 2D drawings and 3D models
- Optional cloud projects and controlled sharing
Your drawings stay under your control
Caddis is local-first: opening a supported file for local review does not require uploading it. If you choose Caddis Cloud, you can continue a project across devices or create a revocable, read-only link.
Frequently asked questions
Do I need an account to use Caddis?
No. You can open and review supported files locally without creating an account. An account is only needed for optional cloud features.
Are my CAD files uploaded?
Not for local viewing. Caddis processes supported files on your device. Cloud storage and share links are opt-in per project.
Can I use Caddis offline?
Local review is designed to work on your device. Cloud sync and share links naturally require an internet connection.
Which CAD formats can Caddis open?
Caddis supports DWG, DXF, STEP, STP, STL, OBJ, PLY, and IFC files in the web viewer.
Explore Caddis tools
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