Based on the answers provided, here are the corrections needed for the 3D object:

1. Adjust the height of the cylinder to be twice its diameter. This is unclear in the current model and needs to be made more apparent.
2. The cylinder needs to be sliced in half at an angle. Currently, it appears that only a small piece has been removed, not half of the cylinder.
3. Ensure that exactly 1/3rd of the material has been removed from the cylinder. The current model does not clearly show this proportion.