Web Worker Unavailable? Troubleshoot by Platform and Environment

Symptoms You'll See

A yellow banner appears at the bottom of Any3D: "Your browser does not support Web Worker." Preview may still work, but large files can freeze the page, and Worker-based paths like texture compression and image-to-model conversion won't be available.

Web Worker lets heavy computation run on background threads. Any3D's texture compression and parts of its conversion pipeline rely on the Worker + OffscreenCanvas + createImageBitmap trio.

Common Causes

Cause	Typical Scenario
Not a secure context	Opened via file://, or served over HTTP (non-localhost)
Outdated browser / WebView	Old system browser, in-app embedded pages
CSP restrictions	Enterprise portal iframe, zero-trust clients injecting worker-src
Extension blocking	Privacy plugins blocking Worker or blob: URLs
Network cache issues	Proxy/VPN returning incomplete Worker scripts
Device management	Managed profiles disabling background scripts

Troubleshoot by Platform

Windows

1. Access Any3D over HTTPS (https://any3d.cc) — don't use a local HTML file.
2. Edge enterprise policies: Check Computer Configuration → Administrative Templates → Microsoft Edge for restrictions on Worker or third-party cookies (which can indirectly affect some Worker loading).
3. Windows Family Safety: Web restrictions on child accounts can cause Worker creation to fail.

macOS

1. Safari and Chrome both require macOS 12+ and a recent browser version.
2. Screen Time → Content & Privacy: if "Limit Adult Websites" or custom filtering is enabled, it may inadvertently block Worker script domains.
3. If a company MDM profile blocks scripting capabilities beyond "Prevent cross-site tracking," contact IT.

Linux

1. Make sure the URL is HTTPS; corporate Squid proxies need to allow blob: and worker-src related requests.

iOS / Android

1. Don't process large files inside in-app browsers (WeChat, DingTalk, etc.); open the link in the system browser.
2. iOS Low Power Mode usually does not disable Workers directly, but older WebKit engines may lack modern APIs—keep your iOS updated.
3. Outdated Android WebView versions can cause Workers to fail: update "Android System WebView" in the Google Play Store.

Networks, VPNs, and Corporate Intranets

Scenario	Details
Corporate VPN	Some VPNs enforce SSL inspection and inject restrictive CSPs; IT needs to allow Workers
Intranet SSO portal iframe	Parent page CSP may forbid worker-src blob:; configure iframe separately or open Any3D in a new tab
Reverse proxy	Nginx/gateway misconfigurations may serve Worker scripts with incorrect MIME types
Router parental controls	Rare for Workers directly, but downgrading to HTTP mirrors will disable Workers

Quick test: Disconnect from VPN or switch to a cellular hotspot to see if the warning disappears.

Enterprise CSP Reference (for IT)

If Any3D is embedded via iframe, ensure the following headers are allowed:

worker-src 'self' blob:;
script-src 'self' 'unsafe-eval' blob:;

Individual users do not need to configure CSP manually.

Step-by-Step Fix (Universal)

1. Verify you are using HTTPS and hard refresh the page (Ctrl+F5 / Cmd+Shift+R).
2. Use Incognito / Private mode to rule out browser extensions.
3. Update your browser and (on Android) update the System WebView.
4. Open Any3D directly in a new tab instead of embedding inside an enterprise portal iframe.

Quick Self-Test

typeof Worker !== "undefined";

Returning true indicates the API exists, though Any3D also requires OffscreenCanvas and createImageBitmap for full Worker pipeline capabilities.

Impact Without Web Worker

Feature	Impact
Vertex compression (Draco, etc.)	Usually still works (main thread + WASM)
Texture / KTX2 compression	Worker path unavailable; large files may freeze UI
Image-to-model conversion	Degraded or noticeably slower performance

Summary

Web Worker warnings typically stem from non-HTTPS origins, outdated WebViews, enterprise CSP/VPN restrictions, or extension blocking. Updating browsers per platform, testing outside corporate networks, and verifying iframe/CSP configurations usually restores background computing capabilities.