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fstl-e vs CAD Assistant: catalog facts
fstl-e	CAD Assistant
Free Free and open source under the MIT licence.	Free Free for personal and commercial use.
Linux	macOS, Android
Opens STL files quickly Configurable background	Opens STEP, IGES and other CAD formats Converts between 3D formats
Viewer only, no editing Small fork maintained by one developer	Viewer and converter only, not a modelling tool Closed source despite being built on the open OCCT kernel
Downloadable app	Downloadable app
Open source	Closed source
License: MIT	License not stated
No account needed	Not stated if an account is needed
Works offline	Works offline
Official website Full listing and sources Checked October 1, 2026	Official website Full listing and sources Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.