There is a point (for example $P(1,1,0)$) and the normal (for example, $n_2(0, 1, 0)$). I need to move the point to the specified distance in the direction that indicates the normal.
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The point can be any, the normal can indicate any direction.
More precisely, I need the opposite direction. But I think I will be able to change the direction.
If $\vec p=(p_x,p_y,p_z)$ is the given point and $\vec n =(n_1,n_2,n_3)$ with $||\vec n ||=1$ is the normalized direction vector, than the point $\vec x$ at distance $d$ from $\vec p$ in the direction $\vec n$ is given by: $$ \vec x= \vec p + d \vec n $$