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

1. Ensure that the triangle is equilateral. This means all sides and angles should be equal. This was unclear in the initial model.

2. Adjust the diameter of the semicircular cutout to be approximately 2/3rd of the length of each side of the triangle. This was also unclear in the initial model. 

Please make these changes while maintaining the triangular shape, the presence of the semicircular cutout, and the one-dimensional extrusion of the object.