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

1. The object needs to be modified to be a flat triangle, as it is currently a polyhedron with multiple faces. 

2. The triangle should be designed as a scalene triangle, with all sides of different lengths. This needs to be clearly visible in the design.

3. The triangle should have one angle that is greater than 90 degrees, making it an obtuse triangle. This should be clearly visible in the design.