Maximum & Minimum constraints

[Shaun v Rooyen]

Is it possible to create an instance Length parameter that has maximum and minimum constraints.
I want to be able to drag the length of a BIC to fit into a space, if the length exceeds lets say 1,5m it no longer can stretch. I then know I have to start the next module.

[aaronrumple]

Should be able to do it with an if statement....

[Shaun v Rooyen]

Aaron, thats what I thought at first. But it keeps creating a "circular chain of references"

[Mike Hardy-Brown]

Zeds,

On your max constraint you need to collapse the instance with the "if" formula.
ie, IF length > xmm, then length = 0
So either collapse it horizontally or vertically.
If this is on the previous shelf, then I will get cracking on it today.

Cheers

[PeterJ]

Can't you do it the other way and and have a limiting length entered in the formula column?

You would have three parameters:

Entered length - where people enter a number
Actual length - the one used by the family created by the formula: if entered length>Constrain length, then constrain length, else entered length.
Constrain length - set by entering in the formula column.

You make your Entered length the one attached to a ref plane that the user can grab a shape handle and you don't expose the Actual length to the rvt file, i.e. it defines the geometry directly not via a ref plane.

You have to go round the houses a little further with the same concept to make a minimum constraint too.

I think that works, but I don't have Revit here to check.