Inject vertex array to shader from a reference surface to use data to do calculations for other suface shading

Questions
1

Hi,
I’m trying to get vertex positions and normals as uniforms from a non planar surface, to use them into a shader applied to another mesh .

here is my code in gltf.scene.traverse:

positionAttribute = child.geometry.getAttribute( 'position' );
normalAttribute = child.geometry.getAttribute( 'normal' ); 
console.log(positionAttribute.array); // this one works
 
                   
uniforms.vRef = positionAttribute.array;
uniforms.nRef = normalAttribute.array;

and uniform is:

uniforms = {

            texture1: { type:"t", value: texture },
            vRef: { value: null },
            nRef: { value: null },
            layers: { value: colors}

        };

Is it right to pass attibute.array? in the shader I get this error:

Uncaught TypeError: Cannot read properties of undefined (reading ‘x’)