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A CAPTCHA based on 3D spatial recognition

A CAPTCHA based on 3D spatial recognition

by Shining_S·Feb 27, 2026·3 points·0 comments
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AI Analysis

●●SolidBig BrainShip It

3D spatial reasoning CAPTCHA — clever premise, but multimodal LLMs will crack this within 12 months.

Strengths
  • •Genuine insight: 3D perception is harder for bots than 2D image classification, at least today.
  • •Two-line integration with reCAPTCHA-compatible flow means zero friction for developers.
  • •WebGL + quaternion math shows solid technical execution, not just a wrapper around existing APIs.
Weaknesses
  • •Durability claim is unproven; vision transformers already interpret 3D structure from 2D images.
  • •No independent security audit or bot evasion attempts published; marketing claims (99.9% blocking) lack evidence.
Category
Security
Target Audience

Web developers and site owners needing bot protection

Similar To

reCAPTCHA · hCaptcha · Cloudflare Turnstile

Post Description

I got tired of clicking traffic lights and fire hydrants, so I built a CAPTCHA that asks you to rotate a 3D object to match a target angle.

Try it here: https://spatial-captcha-frontend.vercel.app

The idea is simple — humans are naturally good at understanding 3D space, but bots aren't. A bot would need to figure out the spatial orientation of a 3D model rendered in a WebGL viewport, which is a much harder problem than solving text or image classification CAPTCHAs.

Under the hood it uses Three.js for rendering, quaternion comparison on the backend for angle matching (45° tolerance), and the whole thing drops into any site with two lines of HTML. Verification flow is the same as reCAPTCHA — pass token issued on success, server-side /siteverify endpoint.

Curious what you all think — is 3D spatial reasoning actually a durable defense, or will multimodal models eat this for breakfast in a year?

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