1. Hidden Surface Removal
In the projection process we project all the faces into the view plane
Some of the faces should not appear in the final images
It is mandatory to remove these invisible surfaces.

2. View Frustum Culling

3. Back and Front Facing

4. Front-to-Back Traversal
Order the object in scene from near to far
Traverse the objects starting from the objects close to the viewer
Maintain a map of the visible/hidden regions
Avoid traversing hidden regions

5. Back-to-Front Traversal
Order the object in scene from far to near
Traverse the objects starting from the objects far from the viewer
Project the object in the order of the traversal.

6. Z-Buffer
A hardware supported Hidden Surface removal approach

7. Z-Buffer

8. Depth Buffer