How to Add 3D to Existing Website
Practical steps to add 3D to existing site: choose Three.js or Spline, add hero scene, optimize for mobile, deploy.
Adding 3D to existing site: (1) Pick your stack — Three.js for code-led teams, Spline for designer-led. (2) Build the hero scene — start with a single 3D model in glTF + Draco, position camera, add basic lighting. (3) Integrate with existing site — load lazy via IntersectionObserver, ensure SEO content stays in HTML. (4) Optimize for mobile — device-tier detection, simpler scene on weak devices. (5) Deploy and monitor — Lighthouse mobile 85+ target. For commercial sites with deadlines, hire a developer; self-learning takes 4-6 weeks.
Further reading
Three resources I recommend after this guide: the official Three.js fundamentals docs (excellent and underused), Bruno Simon's Three.js Journey (paid, comprehensive), and the React Three Fiber docs if you'll work in React. Beyond that, reading other developers' source on GitHub — search for 'three-js portfolio' on GitHub trending — accelerates learning faster than any tutorial.
Prerequisites
Before starting on how to add to, you need: a JavaScript baseline (familiarity with ES modules, async/await, npm), a working local dev environment (Node 18+, a code editor), and a basic mental model of what WebGL renders. You don't need 3D modeling skills — for most tutorials, the assets are provided. Time investment: 2-4 hours of focused work for the basic version.
Step-by-step outline
Step 1: scaffold the project (Vite + Three.js). Step 2: get a basic scene rendering — camera, light, geometry. Step 3: load the asset (glTF). Step 4: hook up animation timeline (GSAP or built-in). Step 5: add interactivity (click, scroll). Step 6: optimize for mobile (device-tier check, asset compression). Step 7: deploy. Each step builds on the previous; skipping leads to confusion later.
Common pitfalls
Three failure modes I see beginners hit: (1) trying to render before assets finish loading — always wait for the loader callback, (2) using full-resolution textures on mobile — always have KTX2 or compressed alternatives, (3) leaving the scene rendering when off-screen — pause the render loop with IntersectionObserver. Each pitfall has a clear fix; the trick is recognizing the symptom.
Frequently asked questions
Is this guide enough to launch a real site?
How does this compare to paid courses?
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What if my visitors are on weak phones?
Ready to ship a 3D experience?
Tell me what you need — fixed price, fixed deadline, no surprises.