I want to know how I can access properties of a mesh using react-three-fiber.

the basic idea should be :

const planeRef = useRef<Mesh>(null);

useFrame(() => {
   if(planeRef.current) {
    //@ts-ignore
    planeRef.current.material.opacity += 0.1
}    

})

However, I cannot access nor can I manipulate the values of planeRef.current.material.opacity.

is there any solution to this ?