Module 

Header 
/Engine/Source/Runtime/Core/Public/Math/Vector.h 
Include 
#include "Math/Vector.h" 
Source 
/Engine/Source/Runtime/Core/Public/Math/Plane.h 
Calculate the projection of a point on the plane defined by counterclockwise (CCW) points A,B,C.
Projection of Point onto plane ABC
Parameter 
Description 

Point 
The point to project onto the plane 
A 
1st of three points in CCW order defining the plane 
B 
2nd of three points in CCW order defining the plane 
C 
3rd of three points in CCW order defining the plane 