3D Animation Creator — Scroll-Driven Video Websites

Content Sourcing

Ask how they want to provide the website content:

• Option A: From an existing website — "Share the URL and I'll pull the real content (product name, features, specs, copy)."
• Option B: Paste it in — "Paste product descriptions, feature lists, specs, testimonials — whatever you have."

If they provide a URL, use WebFetch to retrieve the page and extract relevant copy, product details, features, specs, and any other usable content.

Optional Sections

Ask whether they want these included:

• Testimonials — "Want a testimonials section? Provide them or I'll pull from the URL you shared."
• Confetti — "Want a confetti burst effect anywhere? (e.g., on CTA button click)"
• Card Scanner — "Want a 3D particle showcase section? (Three.js-based — good for showing off a card, device, or object)"

Only include these if the user explicitly opts in.

Prerequisites

• FFmpeg must be installed (brew install ffmpeg if not)
• The user provides a video file (MP4, MOV, WebM, etc.)
• Video should be relatively short (3-10 seconds is ideal)
• The first frame of the video MUST be on a white background. If it isn't, let the user know and ask for a re-export or a separate white-background hero image.

Design System (Built from User's Answers)

Once the interview is complete, construct the design system:

• Fonts: Space Grotesk (headings), Archivo (body), JetBrains Mono (code/mono)
• Accent color: From user's answer — used for buttons, glows, progress bars, highlights
• Background color: From user's answer — used for body, sections
• Text colors: Derived from background — dark bg gets white primary + muted secondary; light bg gets dark primary + muted secondary
• Selection: Accent color background with contrasting text
• Scrollbar: Dark track with gradient thumb using accent color, glow on hover
• Cards: Glass-morphism — semi-transparent bg, subtle border, backdrop-filter: blur(20px), border-radius: 20px
• Buttons: Primary = accent color bg with contrasting text + accent glow; Secondary = transparent with border
• Effects: Floating background orbs (accent color tones, blurred), subtle grid overlay, animated starscape
• Brand name & logo: Used in navbar, footer, loader, and anywhere branding appears

The Build Process

Step 1: Analyze the Video

ffprobe -v quiet -print_format json -show_streams -show_format "{VIDEO_PATH}"

Extract duration, fps, resolution, total frame count. Target 60-150 frames total.

Step 2: Extract Frames

mkdir -p "{OUTPUT_DIR}/frames"
ffmpeg -i "{VIDEO_PATH}" -vf "fps={TARGET_FPS},scale=1920:-2" -q:v 2 "{OUTPUT_DIR}/frames/frame_%04d.jpg"

Use -q:v 2 for high quality JPEG. Use JPEG not PNG for smaller files.

Step 3: Build the Website

Create a single HTML file. The site has these sections (top to bottom):

1. Starscape — Fixed canvas behind everything with ~180 twinkling animated stars
2. Loader — Full-screen with brand logo, "Loading" text, accent-colored progress bar
3. Scroll Progress Bar — Fixed top, accent gradient, 3px tall
4. Navbar — Brand logo + name, transforms from full-width to centered pill on scroll
5. Hero — Title, subtitle, CTA buttons, scroll hint, background orbs + grid
6. Scroll Animation — Sticky canvas with frame sequence, annotation cards with snap-stop
7. Specs — Four stat numbers with count-up animation on scroll
8. Features — Glass-morphism cards in a grid
9. CTA — Call to action section
10. Testimonials — (only if user opted in) Horizontal drag-to-scroll testimonial cards
11. Card Scanner — (only if user opted in) Three.js particle showcase
12. Footer — Brand name and links

For the exact CSS/JS implementation of every section, read references/sections-guide.md. That file contains the complete code for each section — structure, styling, JavaScript, mobile adaptations, and animation patterns.

Step 4: Key Implementation Patterns

Canvas rendering with Retina support:

canvas.width = window.innerWidth * window.devicePixelRatio;
canvas.height = window.innerHeight * window.devicePixelRatio;
canvas.style.width = window.innerWidth + 'px';
canvas.style.height = window.innerHeight + 'px';

Cover-fit drawing (desktop) — zoomed contain-fit (mobile): On desktop, use cover-fit so the frame fills edge-to-edge. On mobile, use a slightly zoomed contain-fit approach so the object stays centered and visible.

Annotation cards with snap-stop scroll: Annotation cards appear at specific scroll progress points (data-show/data-hide attributes). The scroll FREEZES briefly at each card position — creating a "boom, boom, boom" effect where each card pops up as you stop. Uses JS-based snap: detects when scroll progress enters a snap zone, scrolls to the exact position, locks the body overflow for ~600ms, then releases. The number of annotation cards is flexible — match it to the content the user provides.

Navbar scroll-to-pill transform: The navbar starts full-width, then on scroll shrinks to a centered pill shape (max-width ~820px) with rounded corners and glass-morphism background.

Count-up animation: Spec numbers animate from 0 to target with easeOutExpo easing, staggered 200ms apart. Numbers get an accent-color glow pulse while counting. Triggered by IntersectionObserver.

Animated starscape: A fixed canvas behind everything with ~180 stars that slowly drift and twinkle. Each star has random drift speed, twinkle speed/phase, and opacity. Creates a subtle living background.

Step 5: Customize Content

All content comes from the interview (Step 0). Use the real brand name, real product details, and real copy — never use placeholder "Lorem ipsum" text. If content came from a website URL, use the actual text from that site. Populate:

• Hero title and subtitle
• Annotation card labels, descriptions, and stats
• Spec numbers and labels
• Feature cards
• CTA text
• Testimonials (if included)

Step 6: Serve & Test

cd "{OUTPUT_DIR}" && python3 -m http.server 8080

Open http://localhost:8080 and test. Then open the browser URL for the user.

Mobile Responsiveness

Key mobile adaptations:

• Annotation cards: Compact single-line design — hide paragraph text, stat numbers, and labels. Show only card number + title in a flex row. Position at bottom of viewport (bottom: 1.5vh)
• Scroll animation height: 350vh desktop, 300vh tablet, 250vh phone
• Navbar: Hide links on mobile, show only logo + pill shape
• Testimonials (if included): Touch-scrollable, snap to card edges
• Feature cards: Stack to single column
• Specs: 2x2 grid on mobile

Best Practices

1. requestAnimationFrame for drawing — Never draw directly in scroll handler
2. { passive: true } on scroll listener — Enables browser scroll optimizations
3. Canvas with devicePixelRatio — Crisp on Retina displays
4. Preload all frames before showing — No pop-in during scroll
5. Frame deduplication — Only call drawFrame when frame index actually changes
6. No scroll-behavior: smooth — Would interfere with frame-accurate scroll mapping
7. No heavy JS libraries — Pure vanilla JS except Three.js for card scanner (if included)
8. Sticky canvas — position: sticky keeps canvas viewport-fixed while scroll container moves
9. White first frame — The video must start on a clean white background

Error Recovery