perpendicular from vertex to line, to plane?

Do not miss this: http://forums.cgsociety.org/showthread.php?f=98&t=295257

(
	p01 = point pos:[0,0,0]
	p02 = point pos:[100,100,100]
	p03 = point pos:[50,70,90]
	
	function PointLineProjection pA pB pC = 
	(
		local vAB = pB - pA
		local vAC = pC - pA
		local d = dot (normalize vAB) (normalize vAC)
		(pA + ( vAB * ( d * ( length vAC / length vAB) ) ) )
	)
		
	pos = PointLineProjection p01.pos p02.pos p03.pos
	point pos:pos
)

(
	p01 = point pos:[0,0,0]
	p02 = point pos:[100,0,0]
	p03 = point pos:[0,100,0]
	p04 = point pos:[50,70,90]
	
	fn pointPlaneProj pA pB pC pD =
	(
	/*******************************************************************************
		<DOC> Find the projection of a point onto a plane.
		Arguments:
			<point3> pA:				Point on the plane.
			<point3> pB:				Point on the plane.
			<point3> pC:				Point on the plane.
			<point3> pD:				Point to project on the plane.
		Return:
			<point3>	Projected point.
	*******************************************************************************/
		local nABC = normalize (cross (pB - pA) (pC - pA))
		pD + ((dot (pA - pD) nABC) * nABC)
	)
	
	pos = pointPlaneProj p01.pos p02.pos p03.pos p04.pos
	point pos:pos
)

Thank You!

Perfect