secondary-action-mastery

Secondary action adds life to a scene without distracting from the main action. A character walking (primary) while whistling and swinging their arms (secondary). A button pressing (primary) with a subtle ripple effect (secondary). It's the difference between functional animation and rich, immersive motion.

Subordination principle: Secondary action must never compete with primary action. If viewers watch the secondary instead of primary, you've failed. The supporting role must remain supporting.

Reinforcement function: Good secondary action reinforces the primary action's meaning. It doesn't just add motion—it adds dimension to the story being told.

在丰富主要动画、添加支持细节、创建运动深度或使场景感觉生动而不分散主要动作时使用。 来源：dylantarre/animation-principles。