defining a plane

huangyhg

defining a plane
i'm attempting to create an excel spreadsheet that will help me define a plane, based on 3 corner points of a stair landing. i want to do this to determine the overall deflection in relation to the local structure, not to the building structure. this stair is 28' tall and has 6 landings and is only supported by the outside stringers, therefore i am getting proportionately more deflection in the center of the stair. i'm trying to create a spreadsheet that when i enter coordinates and deflections of n1-n3 and add n4 it will give me deflection based against the plane created by n1-n3. is there a simple way to do this in excel does anyone know? please let me know as soon as you can. thanks.
rc
i have created the entire spreadsheet using the lookup function in excel. i have all the data, i'm just wondering how can i easily compute the deflections from the new coordinates = sum(old coordinates and deflections). anyone have this done before? please let me know. thanks.
rc
all that is necessary for the triumph of evil is that good men do nothing.
    edmund burke
please elaborate a little more.
if you have the coordinates and the deflections, you have everything: what are you looking for?
after rereading your first post, i understand that you want to calculate the distance of a point in space from a plane defined by three other points.
in this case:
-represent your plane with the standard equation
afff">x+bfff">y+cfff">z+dfff">=0
-the standard equation is obtained by elaborating the matrix equation:
| x聽 y聽 z聽 1 |
| x1 y1 z1 1 |
| x2 y2 z2 1 |=0
| x3 y3 z3 1 |
the distance is now given by:
δfff">=|afff">x4+bfff">y4+cfff">z4+dfff">|/√(afff">2+bfff">2+cfff">2)
prex
i'm looking for a way to obtain the deflection in relation to the other points, when they make a plane. i want to know the differential deflection across a landing in a stair for cracking issues with the finishes so i can let the architect know what to design his finishes for. i know that i want to represent the plane in the standard equation as mentioned above, and solve it in that fashion. i'm wondering how can i do this in excel? thanks.
rc
rc
all that is necessary for the triumph of evil is that good men do nothing.
    edmund burke
just elaborate the matrix equation and write the resulting equations in excel.
as an example:
afff">=y1z2-z1y2+z1y3-y1z3+y2z3-z2y3
good luck!
prex
i got it figured out.
thanks a lot for your patience on this.
i haven't done matrix work in a year or two and was having a hard time recalling how to do it.
thanks again.
rc
all that is necessary for the triumph of evil is that good men do nothing.
    edmund burke