how look-up table works

[Anonymous]

Dears:

there is diameter to be inputed, but why the inputed valve "77" still can works?

there should not be a norminal diameter of 77, should be 65 then 80

i am confused, for not konwing how look up table works, 

question 1: i can't find any diameter named "Diameter", why i changed the valve , the fitting changed?

question 2: acoording to formular if can't  seach the vlave in table the return valve will "0", why i input 77 , no "0" come out

question 3:  i found the parameter unit is inch, is that the reason cause this 77 happened?

question 4: document stated "Lookup tables are used for pipe and conduit families to define parameter values in an external comma-separated values (CSV) file." ,then what if i want to use lookup table for c-channel, can it still work?

qustion 5: document stated:

LookupValue(1-N)

value to find in the first, second, and subsequent columns of the table. (When looking up values, the first column is skipped.)

then which case are the first column will not skipped?

[fabiosato · Accepted solution]

Hello,

There is a tutorial for lookup tables in Revit Help.

1. The diameter in the option bar corresponds to the valeu assigned to the connectors, in your family, it may correspond to Nominal Diameter, to be sure only checking the family.

2 and 3. It seems that the lookup table is in imperial units, and 77 may correspond to 5 inches.

4. Lookup tables work in any category of families.

5. When you want to extract the text value from the first colunm, with the formula sizer_lookup(Table, "", "not found", Nominal Diameter) for example.

[Anonymous]

thanks, i just leaved it alone.