static getInterpolatedAttribute( attr, i1, i2, i3, barycoord, target ) {

		_v40.setScalar( 0 );
		_v41.setScalar( 0 );
		_v42.setScalar( 0 );

		_v40.fromBufferAttribute( attr, i1 );
		_v41.fromBufferAttribute( attr, i2 );
		_v42.fromBufferAttribute( attr, i3 );

		target.setScalar( 0 );
		target.addScaledVector( _v40, barycoord.x );
		target.addScaledVector( _v41, barycoord.y );
		target.addScaledVector( _v42, barycoord.z );

		return target;

	}
Computes the value barycentrically interpolated for the given attribute and indices.

@param {BufferAttribute} attr - The attribute to interpolate.
@param {number} i1 - Index of first vertex.
@param {number} i2 - Index of second vertex.
@param {number} i3 - Index of third vertex.
@param {Vector3} barycoord - The barycoordinate value to use to interpolate.
@param {Vector3} target - The target vector that is used to store the method's result.
@return {Vector3} The interpolated attribute value.