Spark AR中如何获取Deformation对象并通过JS修改其属性？

I've run into this exact issue before when working with Spark AR's face distortion packs! The key mistake here is assuming the faceDistortionPack is a child of the FaceMesh or accessible via a direct deformation property—instead, morph objects live in the FaceMesh's morphers array.

Spark AR stores all morph targets applied to a FaceMesh in the morphers collection. Your facemesh_distortion FaceMesh does have the faceDistortionPack attached to it, but you need to pull it from that array instead of using find() directly on the FaceMesh.

Corrected Code Example #

Here's how to properly retrieve the morph object and modify properties like nose_z:

const Scene = require('Scene');
const Diagnostics = require('Diagnostics');

// Wait for the FaceMesh to load fully to avoid null references
(async function () {
  const faceMesh = await Scene.root.findFirst('facemesh_distortion');
  
  // Locate the faceDistortionPack in the morphers array by name
  const distortionPack = faceMesh.morphers.find(morph => morph.name === 'faceDistortionPack');
  
  if (distortionPack) {
    Diagnostics.log('Successfully found distortion pack: ' + distortionPack.name);
    
    // Set a static value for the nose_z property (typical range: 0 to 1)
    distortionPack.setValue('nose_z', 0.7);
    
    // For dynamic control (e.g., binding to a UI slider), use this instead:
    // const slider = await Scene.root.findFirst('distortionSlider');
    // distortionPack.inputs.set('nose_z', slider.value);
  } else {
    Diagnostics.log('Failed to locate faceDistortionPack morph target!');
  }
})();

Why Your Original Code Failed #

• faceMesh.deformation returns null because this property is designed for mesh deformation modifiers, not pre-built morph target packs like the face distortion assets.
• faceMesh.find('faceDistortionPack') throws an error because find() searches for direct child scene objects, and morphers aren't stored as children—they're a separate, attached collection on the FaceMesh itself.

Key Notes #

• Always use async/await or promises when accessing scene objects to ensure they're fully loaded before interaction.
• Most morph target property values range from 0 (no distortion) to 1 (full effect), but you can test values outside this range for extreme distortions if needed.

内容的提问来源于stack exchange，提问作者tv1st