Optimizing Lottie Animations with CSS Preloading in Web Projects

When it comes to creating engaging web interactions, animations like Lottie files are a popular choice. However, managing their loading performance can be tricky, especially when aiming for seamless user experiences. I recently encountered a challenge while replacing a Lottie animation with pure CSS and JavaScript: ensuring that all the image frames preload correctly to prevent flickering and layout shifts on initial hover.

Background Context

In a personal web development project, I reverted a Webflow-designed animated element into a custom HTML, CSS, and JavaScript implementation. The original feature involved a Lottie animation that simulated a 3D rotation of energy cans on hover. While the animation looked great, the first interaction caused all frames to load simultaneously, leading to visual glitches like blinking and shifting content, which detracted from the user experience.

Attempted Solutions

To resolve this, I tried preloading the individual image frames using JavaScript, aiming to load all necessary assets before the user interacts with the element. I also experimented with programmatically triggering the animation on page load to cache the frames. Unfortunately, these approaches did not fully eliminate the flickering or performance hiccups.

Seeking a Better Approach

This experience highlights the importance of efficient preloading strategies when replacing complex animations with CSS or sprite-based techniques. Properly preloading images ensures that animations play smoothly on first interaction without causing delays or visual disruptions.

If you’re tackling a similar challenge, consider the following tips:

• Use JavaScript to preload all animation frames on page load, ensuring they are ready in the browser cache.

• Utilize CSS techniques like sprite images or CSS animations where feasible to minimize asset requests.

• Trigger a “dummy” animation on page load to prime the animation frames, reducing the initial load impact.

• Optimize image sizes and formats for faster loading times.

For reference and to explore the current implementation, you can visit the live project here:

https://mitchangus.design/LiftOff

Final Thoughts

While replacing Lottie animations with CSS can offer performance improvements, managing initial load times remains crucial. Proper preloading and thoughtful animation strategies can significantly enhance the user experience by providing smooth and flicker-free interactions.

Have you faced similar challenges with web animations? Share your insights and solutions in the comments!