The tree(3D) ←→ Camera(2D) The tree : The point we're seeing with our eyes, 3D point which has world coordinateCamera : When we take the tree, it transforms to 2D 3D Projection Geometry:The camera is at point C (camera center).A 3D point in space is projected through the pinhole onto the image plane.The image plane is in front of the camera in this drawing, which is a convention to avoid flippin..