# Building Tactile UX with Intentional Lottie Design How to create satisfying interactions without physics engines - **Source:** [Articles on Smashing Magazine — For Web Designers And Developers](https://brifing.si/source/e66a90c0-835e-4d99-8b50-d2215183ea28) - **Published:** 2026-08-11 - **Topic:** [Design & UX](https://brifing.si/c/design) - **Original article:** - **On Brifing:** https://brifing.si/s/7f1887dc-6bf4-4a76-8554-82ac243c23bf ## Designer Control Over Physics Engines In the Stress Release project, programmatic Lottie control was chosen over traditional physics engines. Animations needed to move exactly as designers intended. For example, a 'mega squeeze' reaction required a specific 181-frame sequence. This approach prevented algorithmic approximations from overriding the designers' original work. ## Deterministic Animation Control The core requirement was completely predictable animations. Using Lottie's native API, each click triggered specific animation segments. This created perfect harmony between user interaction and animation layers. The control mechanism proved especially critical for fast feedback loops where timing precision matters most. ## Radial Input Mapping System A radial system was developed to process click locations. Each click was positioned relative to the character's center point, with distance calculated using the Pythagorean theorem. This distance determined scoring, feedback intensity, and explosion placement. For instance, clicks within 10 pixels scored 100 points. ## Dartboard-like Scoring Zones Concentric scoring zones were created around characters, resembling a dartboard. Clicks beyond 145 pixels scored zero, while closer hits earned more points. This system replaced random number generation with mathematical precision, making game mechanics more satisfying. The zones created clear visual feedback for user actions. ## Position-Aware Animation Placement Explosion animations appeared exactly where users clicked, achieved through DOM positioning and CSS margins. On mobile devices, a -20px offset was applied. This mechanism strengthened tactile feedback by creating a clear 'I hit that spot' sensation. The spatial accuracy significantly enhanced the interactive experience. ## Animation Segment Management Each character had defined animation segments: idle loops, reaction frames, and end states. For example, a character's light reaction spanned frames 41-80. User interactions triggered transitions between these predefined segments, maintaining narrative control. This structure allowed precise timing for emotional impact. ## Cross-Platform Compatibility Using DOM-based SVG elements enabled consistent handling of both desktop clicks and mobile touch interactions. This approach maintained alignment between how animations rendered and how interactions were processed, without requiring additional coordinate transformation layers. The system worked seamlessly across devices. ## Performance Optimization Avoiding heavy solutions like WebGL or Matter.js kept the system lightweight. Lottie's built-in SVG renderer handled complex vector animations smoothly. This translated to higher frame rates and better battery life, especially on mobile devices. The efficient architecture supported complex interactions without performance penalties. ## Harmony Between Design and Technology This project demonstrated how original design vision can align with technical implementation. By using fully designed motions instead of physics engine randomness, it created more controlled and satisfying user experiences. The approach sets a new standard for interactive projects requiring emotional responses, proving intentional design can outperform algorithmic approximations. ## Sources covering this story - https://smashingmagazine.com/2026/08/building-tactile-ux-honoring-intentional-design-lottie/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._