English: Illustration of the 3D orthogonal projection of a point ${\displaystyle x}$ onto a plane ${\displaystyle E}$ with initial point ${\displaystyle r_{0}}$ and orthogonal direction vectors ${\displaystyle u}$ and ${\displaystyle v}$, which yields as intermediate points ${\displaystyle P_{g}(x)}$ and ${\displaystyle P_{h}(x)}$ on the lines ${\displaystyle g}$ and ${\displaystyle h}$ and ${\displaystyle P_{E}(x)}$ as the final projected point.