About this demo

This demo is a shoe explorer that features 3D-models of several shoes. The 3D-models are linked to a Scroll-Driven Animation, so that they rotate as you scroll.

The Code / Explanation

Each .card has a 3D-model (.glb) loaded that is displayed through <model-viewer>. The model is set to non-interactive, so you can’t directly control it.

A View Timeline is attached to each .card, which is used to drive all animation effects: the footer fading in and the title revealing itself.

.card {
	view-timeline: --card inline;

	& h2 {
		animation: clip-in linear backwards, clip-out linear forwards;
		animation-timeline: --card;
		animation-range: entry 50% entry 100%, exit 0% exit 50%;
	}

	& footer {
		animation: fade-in linear both, fade-out linear both;
		animation-timeline: --card;
		animation-range: cover 40% cover 50%, cover 50% cover 60%;
	}
}

To sync the progress of the animation effect, the trackAnimationProgress helper is used. It constantly reads the animation’s progress in a requestAnimationFrame.

const trackAnimationProgress = (animation, cb, precision = 5) => {
	let progress = 0;
	const updateValue = () => {
		if (animation && animation.currentTime) {
			let newProgress = animation.effect.getComputedTiming().progress * 1;
			if (animation.playState === "finished") newProgress = 1;
			newProgress = Math.max(0.0, Math.min(1.0, newProgress)).toFixed(precision);

			if (newProgress != progress) {
				progress = newProgress;
				cb(progress);
			}
		}
		requestAnimationFrame(updateValue);
	};
	requestAnimationFrame(updateValue);
}

This helper is hooked up to an empty animation that is attached to the card. The resulting progress value is used for the rotation of the 3D-model

.card {
	animation: empty linear forwards;
	animation-timeline: --card;
}

import { trackAnimationProgress } from '/shared/util.js';

document.querySelectorAll('.card:has(h2)').forEach($card => {
	const model = $card.querySelector(':scope > model-viewer');

	trackAnimationProgress($card.getAnimations()[0], (progress) => {
		model.orientation = `0deg 0deg ${progress * (-360 - 90)}deg`;
	});
});