1 ) A method comprising: receiving, at a printing device comprising a processor, reflectance properties comprising at least disparate components associated with diffuse data and specular data of an object surface; determining, by the device using the object specular data, 3D model specular data for a surface of a 3D model of the object, the determination of the 3D model specular data based on determining correspondence of respective 3D model specular data of a surface portion of the 3D model with respective object specular data of a corresponding portion of the object surface; and generating, by the device, the 3D model of the object, the surface of the 3D model being constructed by the device to comprise the 3D model specular data corresponding to the object specular data.