How do I work out the value of Z in a plane?

Question

Inputs are xy and z of the three points of a triangle whichich forms a plane plane and x and y for a point within the plane. I require z for this value.

Thanks

Answer 1

your building a real plane or a RC one?

Answer 2

Try:
jblanco_60.tripod.com/plane.html

that is plane.html at the end (for some reason the answer isn't showing right)

Type in the values for your points and get the equation (standard form) for the plane. Then put in the X and Y for the point in the plane and solve for Z. This will only work if you don't have to show your work on how you got the equation for the plane.

Answer 3

Man its been awhile. usually when you have the equation for the plane those values 5x +5y +7z are also your normal vector. so thus a dot product of that vector with the vector that runs through your x and y point = 0.
So thus:

say you are given 6 and 7 for x and y

(5,5,7)dot(6,7,z) =0

then solve for z

Answer 4

Take the three given points that define the plane and work up the equation of the plane. Suppose you get:

ax + by + cz + d = 0

Now suppose you have one more point (x',y',z'). You know x' and y' but not z'. Plug in the values x' and y' and solve for z'.

ax' + by' + cz' + d = 0
cz' = -ax' - by' - d
z' = (-ax' - by' - d)/c