This paper presents a technique for embedding information into a 3D object. The technique can rewrite the information non-destructively. Information can be rewritten into the object using magnetization and demagnetization from the outside of the fabricated object. We are studying the factors that can make more clear readability and effective rewritability in embedding data into 3D objects. One factor is the amount of magnetic filament that we use for representing the information in each position. We found that the strength of the magnetic field varies in accordance with the amount of filament. In this way, we can control the size, frequency, and capacity of future embedded information.