Designing 3D models for 3D printing is sometimes annoying, because the 3D models used for 3D printing do not have a completely unified standard. Different modeling software, different printing materials, and different printer models even mean completely different 3D printing technologies, which will reflect the different requirements for 3D models. So as a 3D designer, if you find it difficult to design a useful 3D printed model, it is simply too normal. Here, I briefly summarized several problems that are prone to occur in the process of converting 3D models into real objects.