Motion design principles are the secret sauce of engaging UIs. They bring static elements to life, guiding users through interfaces with natural, fluid movements. From anticipation to follow-through, these techniques create animations that feel intuitive and responsive.

Timing, pacing, and motion paths are the building blocks of effective UI animations. By mastering easing curves, perfecting animation durations, and crafting natural trajectories, designers can create interfaces that are not just functional, but delightful to use.

Animation Principles

Foundational Animation Techniques

• Anticipation prepares viewers for upcoming action by showing preparatory movements
• Follow-through extends motion beyond the main action to create natural, fluid movement
• Squash and stretch exaggerates deformation of objects to convey weight and flexibility
• Secondary action adds subtle movements to support the main action, enhancing realism
  • Includes hair swaying or clothing rippling as a character moves
• Exaggeration amplifies key elements of motion to create more impactful and expressive animations
• Appeal focuses on creating visually pleasing and engaging character designs and movements

Applying Animation Principles in UI Design

• Anticipation in UI animations signals impending changes (button hover effects)
• Follow-through adds polish to UI transitions (menu items continuing to move slightly after opening)
• Squash and stretch brings life to UI elements (icons compressing when clicked)
• Secondary action enhances UI feedback (ripple effect spreading from touch point)
• Exaggeration draws attention to important UI elements or actions (bouncing notification icons)
• Appeal in UI design creates visually harmonious and inviting interfaces

Timing and Pacing

Easing and Motion Curves

• Easing adjusts the rate of change in animation to create more natural, dynamic motion
• Timing controls the speed and rhythm of animations, affecting perceived realism and impact
• Slow in and slow out (also known as ease-in and ease-out) gradually accelerates and decelerates animations
  • Mimics real-world physics where objects rarely start or stop instantly
• Linear motion maintains constant speed throughout animation, often appearing unnatural
• Ease-in-out combines gradual acceleration at the start with deceleration at the end
• Custom easing curves allow fine-tuned control over animation speed at different points

Implementing Effective Timing in UI Animations

• Fast animations (100-200ms) convey responsiveness for small UI changes (button clicks)
• Medium animations (200-500ms) suit most standard UI transitions (menu openings, page transitions)
• Slow animations (500ms+) emphasize important changes or create dramatic effects
• Consistent timing across similar UI elements maintains a cohesive feel
• Varying animation durations can create hierarchy and guide user attention
• Simultaneous vs. sequential timing of multiple elements affects perceived complexity and flow

Motion Paths

Designing Natural Movement Trajectories

• Arc motion paths create more natural, organic movement compared to straight lines
  • Reflects how objects move in the physical world (falling leaves, bouncing balls)
• Staging arranges elements and motion to guide viewer attention effectively
  • Considers composition, timing, and spatial relationships between elements
• Straight motion paths can convey efficiency or mechanical movement (robotic arm)
• Spiral motion paths add dynamic energy to animations (loading spinners)
• Bouncing motion paths combine arcs with changes in direction (realistic ball physics)

Implementing Motion Paths in User Interfaces

• Arc motion enhances natural feel of draggable UI elements
• Staging guides users through multi-step processes or onboarding flows
• Combine different motion paths to create complex, engaging animations
  • Particle effects often use multiple motion paths simultaneously
• Motion paths can reinforce brand identity and personality in UI animations
• Consider device orientation and screen size when designing motion paths for responsive interfaces