Based on the answers provided, the following corrections need to be made to the 3D object:

1. A smaller rectangular prism needs to be cut out from the original shape. 
2. The width of the cut out should be the same as the width of the original shape.
3. The length of the cut out should be 1/4th the length of the original shape.
4. The height of the cut out should be 3/4th the height of the original shape. 

Please ensure that these changes do not alter the overall shape of the object, which is a long rectangular prism.