# Floor Determination • ### Question

•  I get the equation,Ax + By + Cz + D
where:
A = vFloorClipPlane.x

B = vFloorClipPlane.y

C = vFloorClipPlane.z

D = vFloorClipPlane.w

Does it represent the floor plane in the photo?

And sum = Ax + By + Cz + D, what is the meaning of "sum = 1.2xxxx"?

Is it representing the distance in meter between the plane and (x,y,z)?

• Edited by Tuesday, January 17, 2012 1:10 PM
Tuesday, January 17, 2012 1:02 PM

### All replies

• It is supposed to be the plane of the floor with respect to the camera.  The equation that you listed is the plane equation of the floor when the origin is at the camera center.  At that point, x=y=z=0, so you are left with only D which should represent the negative of the height of the camera off of the floor.

If you plug in other <x,y,z> coordinates, then you will get the distance from that point to the floor plane.  This is the shortest distance to the plane, which means a vector perpendicular to the plane is made to your point, and then take the length of that vector gives you the distance.

• Proposed as answer by Monday, May 7, 2012 6:42 AM
Thursday, January 19, 2012 10:38 PM