How do I find the projection of a point onto a plane Lets say I have the point $(x, y, z)$ and the plane with normal $(a, b, c)$ with the point $(d, e, f)$. I am trying to use this in $3D$ programming.  Thank you!

Let us denote your point as $(x_0,y_0,z_0)$ instead of $(x,y,z)$ and projection as $(x'_0,y'_0,z'_0)$
Parametric equation of the line that passes through point and its projection is given by :
$x'_0=x_0+a\cdot t$
$y'_0=y_0+b\cdot t$
$z'_0=z_0+c\cdot t$
Equation of the plane is :
$a \cdot(x-d)+b\cdot(y-e)+c\cdot(z-f)=0$
Now , since point $(x'_0,y'_0,z'_0)$ belongs to the plane you have to substitute its coordinates into equation of the plane instead of $x,y,z$ and calculate parameter $t$ .
