Is there a way to project a vector3 onto a plane?

Question

I'm aware of being able to do so onto another vector, but I need to be able to do functionally the same along 2 vectors, or a plane, decided by an object other than the one I want to move along the plane. I'm effectively trying to flatten vectors onto a plane.

As a practical example, I have a player in first person view who wants to climb a wall. The direction of his camera is what he uses to decide his direction, but his actual movement is limited to be along a plane of the climbable surface.

Answer 1

Answer by robertbu · Nov 11, 2014 at 08:12 PM

Here are two functions. The ProjectVectorOnPlane() is untested and uses Vector3.zero for the plane point.

 function ProjectVectorOnPlane(planeNormal : Vector3,  v : Vector3 ) : Vector3 {
     planeNormal.Normalize();
     var distance = -Vector3.Dot(planeNormal.normalized, v);
     return v + planeNormal * distance;
 }    
 
 function ProjectPointOnPlane(planeNormal : Vector3 , planePoint : Vector3 , point : Vector3 ) : Vector3 {
     planeNormal.Normalize();
     var distance = -Vector3.Dot(planeNormal.normalized, (point - planePoint));
     return point + planeNormal * distance;
 }

Add comment · Show 1 · Share

klesun · Aug 20, 2016 at 10:26 PM 3

Share

You normalized the normalized normal

Answer 2

Answer by gw1108 · Dec 14, 2016 at 06:54 AM

You can just use Vector3.ProjectOnPlane(Vector3 vector, Vector3 planeNormal);

More info here: https://docs.unity3d.com/ScriptReference/Vector3.ProjectOnPlane.html

Add comment · Share

Is there a way to project a vector3 onto a plane?

2 Replies

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions