About StepPDF 3D
About us
StepPDF 3D is a free tool for viewing CAD models and converting them into interactive 3D PDFs right in your browser — nothing to install, no sign-up and no files uploaded to any server.
Why it exists
Sharing a 3D model with someone who doesn’t have CAD software is usually awkward: screenshots that can’t be rotated, viewers that require an account, or services that make you upload confidential designs to someone else’s servers. A 3D PDF solves much of that, because the recipient only needs a compatible PDF reader — but the tools to create one are usually paid or part of professional suites.
StepPDF 3D was built to fill that gap: a fast, free way to turn a STEP file into a real 3D PDF that can be rotated, zoomed and explored part by part.
How we do it
Privacy by design
Your file is processed in your browser. Your designs are never uploaded to a server, which protects the intellectual property of your parts and projects.
Real 3D, not images
The PDF contains the model in PRC format, with its part structure, colors and predefined views. It is not a screenshot.
Open technology
We use OpenCascade (through occt-import-js) to read STEP and IGES, three.js for the viewer and our own PRC writer based on Asymptote’s.
Technical honesty
We state which formats are supported, what files we tested them with and which are experimental, and we don’t pretend to support closed native formats such as SolidWorks or CATIA.
Who is behind it
StepPDF 3D is an independent project created and maintained by Engineer Said Ayup from Mexico. The site is free and funded by advertising, which lets us keep improving it without charging the people who use it.
Who it’s for
Engineers, industrial designers, manufacturers, machine shops and 3D printing services, students and anyone who needs to show a 3D model to customers, suppliers or colleagues who don’t use CAD software.
Contact
We love getting suggestions and bug reports. Write to contact@stepto3dpdf.com or visit the contact page.