How can I fix initial animation stuttering in threejs with Blender-imported animations?

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Animation Stuttering in Three.js

Based on your description, you're experiencing stuttering when using React Spring to control animations imported from Blender. This is a common issue that could be related to several factors:

Possible Causes and Solutions

1. Animation Timing and Interpolation:

   • React Spring uses its own interpolation system which might differ from Blender's
   • Three.js's native animation system (AnimationMixer) is specifically optimized for 3D animations

2. Consider Using Three.js Native Animation System:
   Instead of React Spring, you might want to try Three.js's built-in animation system:

   JAVASCRIPTCopied
   import { useEffect, useRef } from 'react';
   import { AnimationMixer, Clock } from 'three';
   import { useFrame } from '@react-three/fiber';
   
   function AnimatedModel({ gltf }) {
     const mixer = useRef();
     const clock = useRef(new Clock());
   
     useEffect(() => {
       if (gltf && gltf.animations && gltf.animations.length) {
         mixer.current = new AnimationMixer(gltf.scene);
         const action = mixer.current.clipAction(gltf.animations[0]);
         action.play();
       }
     }, [gltf]);
   
     useFrame(() => {
       if (mixer.current) {
         mixer.current.update(clock.current.getDelta());
       }
     });
   
     return gltf ? <primitive object={gltf.scene} /> : null;
   }

3. Synchronizing Multiple Animations:
   If you need to synchronize multiple animations, you can use the same mixer for all of them:

   JAVASCRIPTCopied
   // Create a shared mixer
   const mixer = new AnimationMixer(scene);
   
   // For each model
   const action1 = mixer.clipAction(animation1);
   const action2 = mixer.clipAction(animation2);
   
   // Start both animations
   action1.play();
   action2.play();
   
   // Update in animation loop
   mixer.update(delta);

4. Performance Optimization:

   • Ensure your animation frame rate is consistent
   • Consider using requestAnimationFrame directly for more control
   • Check if there are too many vertices or complex operations happening simultaneously

5. Animation Easing:
   React Spring's default easing might be causing the stuttering. Try adjusting the configuration:

   JAVASCRIPTCopied
   useSpring({
     position: [0, 1, 0],
     from: { position: [0, 0, 0] },
     config: { tension: 170, friction: 26 } // Adjust these values
   });

If you need more specific help, I'd need to see more details about your animation setup and the exact nature of the stuttering.