以前讲过的一点透视和两点透视的画法,都是以铅垂地面作为画面的,而三点透视图则是以倾斜于基面的平面为画面的,此画面与地面有一倾角。因为在作三点透视图时,若视轴倾斜而画面竖直,便会产生不自然的畸形,因而画面也要倾斜,与视轴垂直,这样就出现了三个交点。 The point-and-point and two-point perspective painting techniques mentioned above all use the vertical ground as a picture, while the three-point perspective view is based on a plane inclined to the base surface. This picture has a tilt angle with the ground. Because in the three-point perspective view, if the visual axis is tilted and the picture is vertical, it will produce an unnatural malformation, and therefore the picture must also be tilted, perpendicular to the visual axis, so that there are three intersections.