How are the 3D object models generated?

Hello, I'm trying to evaluate 6D object pose tracking on a custom object. So I'm wondering how the 3D model is generated. I checked the power_drill 3D model from YCB_video and YCB dataset. Seems they are different. May I know how you generated the 3D model? Is it from a dedicated 3D scanner or reconstructed from other software? 