the third variable comes into play in the table - for example:
with system 1, and a .30 COG, my index and match functions will call this:
0.014*F7 + 1.50
the F7 is my third variable - the percent vision. So, the 2 dimensional
lookup is not enough for what i need - i need a lookup which looks up the
equation, but than can plug in a value for the percent, depending on what
sheet is calling the equation in the first place - since the % vision is
calculated on another sheet, and changes in every new sheet.
Sorry that this is a little confusing... it's a complicated thing im trying.

"T. Valko" wrote:

Sorry, I'm not following you on this.

If you have a 2 dimensional lookup table where does the 3rd variable come
into play?

--
Biff
Microsoft Excel MVP


"Derrick" wrote in message
...
sorry.
i have to do some thermal calculations with 3 variables:
system type (so a text)
window vision %,
and Glass COG ( another category)
so far, i've set up a chart on a data sheet with the x axis the COG, and y
axis a System type.
where those two meet, i'm i have a linear equation (y= mx + b), where y is
the thermal calc i need, and x is the window percent.

My problem lies where i need to 'call' that equation from the data sheet,
take it to a window frame sheet, and somehow imput a calculated % into the
linear equation.
these percents change, so i can't just plug it in to all the equations.

My question is: can i do that somehow? is it also possible to call a
sheet
a variable, so that if the equation is successfully called, it will input
a
percent that the sheet that called it has calculated?

Hopefully that's a little more detailed...

"T. Valko" wrote:

Not enough detail

--
Biff
Microsoft Excel MVP


"Derrick" wrote in message
...
is there a way to use an array or something similar to calculate a 3
variable
problem, so that different sheets can reference a formula on another
sheet,
and come up with different values, without having multiple formulas?

something similar to 3D arrays?
i've been using the index function with 2 nested match functions, but
that
only helps with 2 variables