Parent Article: DrawIn3D.htm We call lens transformation ... IsometryWe call lens transformation:r~R/Z, where r=(x,y) - human eye bottom or monitor screen coordinates, R=(X,Y), X,Y,Z - coordinates of point in "3D World" to be projected to a screen, Z axiz is perpendicular to a screen. Here are more details. (Choice of Z-axis is different than above.): Sketch 0 0 Sketch 0 1