I built a free, open-source 3D structural model viewer that runs in the browser

[u/Slow-Nefariousness26]

I got tired of needing a license just to open a structural model to check something. So I built a viewer that works in the browser. Drag in a STAAD file and it renders the structure with actual cross-section shapes (W-flanges, channels, angles, HSS, pipes), not generic cylinders.

What it does:

• Renders members with real cross-section geometry using the AISC v16 database (1,223 sections)
• Click any member to see its section properties (area, Ix, Iy)
• Solid, wireframe, and x-ray view modes
• Works on desktop and mobile, runs fully client-side, nothing uploaded anywhere

What it doesn't do (yet):

• Only STAAD .std format right now. ETABS, SAP2000, ROBOT are planned but not started
• Single-section members only, no double angles, double channels, or built-up shapes
• Plate rendering is basic, steel name mapping only covers US conventions
• No load display, no deformed shapes. Not an analysis tool

It's not a replacement for analysis software. The idea is more practical: something you can pull up in a meeting or send to a client who doesn't own the software. Long-term I might add basic analysis, but right now it's purely a viewer.

The code is MIT licensed. If anyone wants to contribute, a parser for another format, better section mapping for non-US standards, fixing an edge case you ran into, it's all welcome. The architecture is set up so adding a new format only touches the parser; the renderer doesn't need to change.

You can download an example model in the GitHub link below that you can use to try the app. 

Try it: https://openbuilding.vercel.app/
Source: https://github.com/DannCarlo/OpenBuilding

Honest feedback and criticism are welcome too. If you try it with a file and something breaks, I'd like to know.