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

1. No changes are required in terms of the object's resemblance to a right-angled triangle and its extrusion in one dimension as these aspects have been correctly implemented.

2. The height of the triangle is unclear. Please ensure that the height of the triangle is more than twice the base. This should be visually apparent in the 3D model.

3. The triangle is currently not hollow. Please modify the 3D model to make the triangle hollow. This should be visible from the images of the 3D model.