:I can to provide pictures, to show the problem. If object if in center of the screen, then object shape is good, but if you move mouse to right, then object will be on left side and will be longer. And if you move computer mouse down, then object will be longer than when object was in center of screen. And if you move mouse to corner, then object will be in wrong shape and will be bigger than on center. And those shape distortions do not depending on how far or how close object is. Need somehow to remove some part of vertical and horizontal lines from rendered image and need remove proportionally depending on how far this visible lines are from center. Or need to change all 3D algorithms. So if objects is not correctly rendered if his position is far from screen center, then is possibility in ray trancing when need to refract rays in glass there also can be serious distortions or all rays can go wrong, because algorithm pretty stupid and don't have real lens and iris of real certain size, but some perspective only in one axis (say this axis x into deep, and over axis do not have perspective - distance felling, like perpendicular line to corner is the same distance for algorithm, like line along center into deep/far distance and thats why objects become with distorted shape).