The observation in grade four is more intuitive, and the observation in grade five is more difficult. 1. Generally speaking, we can observe an object from the front, left and top respectively. The picture from the front is called the main view, the picture from the left is called the left view, and the picture from above is called the top view. The front view, left view and top view of an object are collectively called the three views of this object. 2. The shapes of objects observed from different directions are often different. From the front, the graphics are not necessarily the same as from the back. From the left, the figure you see is not necessarily the same as that from the right. Seen from above, the figure is not necessarily the same as that seen from below. If we want to draw three views of an object, we can imagine that there is a plane in the corresponding direction, and then project the object onto the plane, then this projection is the figure we want to draw.