Revit Formula - if yes/no checked, then override value, else use entered value

[Anonymous]

I have 3 instance parameters, call them yn, val1, val2. Val1 and val2 each control the height of a different element in a family. I want y/n to control whether they are aligned or can move independent of one another. I know this is can be done by creating an extra parameter to use as a placeholder for the override value (e.g. val3 = if(yn, val1, val2)), but I'd like to avoid wasting a parameter if possible.

TL;DR  is there a formula function for overriding a parameter value? -> val2 = if(yn, val1, val2) returns circular reference error.

Thanks

[barthbradley]

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@Anonymous wrote:

I have 3 instance parameters, call them yn, val1, val2. Val1 and val2 each control the height of a different element in a family. I want y/n to control whether they are aligned or can move independent of one another. I know this is can be done by creating an extra parameter to use as a placeholder for the override value (e.g. val3 = if(yn, val1, val2)), but I'd like to avoid wasting a parameter if possible.

TL;DR  is there a formula function for overriding a parameter value? -> val2 = if(yn, val1, val2) returns circular reference error.

Thanks

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Not clear.  You have 4 Parameters don't you? I mean there's a Parameter that accepts either val1 or val2 depending on the status of y/n; right?    

...can you post a picture or something? Also, will this question on the finals?  

[Anonymous]

@barthbradley

I know I can accomplish what I want using 4 parameters, just wondering if its possible with only 3.

[barthbradley]

Don't know. Need more info. I work best when illustrations accompany the explanation. 

[Anonymous]

[ToanDN]

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@Anonymous wrote:

I have 3 instance parameters, call them yn, val1, val2. Val1 and val2 each control the height of a different element in a family. I want y/n to control whether they are aligned or can move independent of one another. I know this is can be done by creating an extra parameter to use as a placeholder for the override value (e.g. val3 = if(yn, val1, val2)), but I'd like to avoid wasting a parameter if possible.

TL;DR  is there a formula function for overriding a parameter value? -> val2 = if(yn, val1, val2) returns circular reference error.

Thanks

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[barthbradley]

LOL! Thanks for the detailed illustration, @Anonymous.  I'm dropping the class. Home Economics here I come. 

[Anonymous]

@ToanDN

So, to be explicit, no there is no function for that; yes you have to use 4 parameters?

[barthbradley · Accepted solution]

Yes; that is correct. Promise. 

...however...you can NEST if statements.  

...I've had a hardcopy of this pinned above my workstation for years:  

https://www.revitforum.org/tutorials-tips-tricks/1046-revit-formulas-everyday-usage.html

[Anonymous]

Great resource, much thanks!

[dani52g7]

Hi, any chance you still have a hard copy? I can't reach the link... Thank you!

[ToanDN]

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@dani52g7 wrote:

Hi, any chance you still have a hard copy? I can't reach the link... Thank you!

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https://www.revitforum.org/node/1126

[jfiferMJ4ME]

Did you ever solve This? Even still, I have to use an extra parameter, which kills the instance ability to move with draggers, and gets confusing when the distance location parameter reads wrong (because its value isn't being utilized while the sink is centered. Trying to have a sink countertop family that can be centered with a button, but can be free when it's unchecked. Currently it is: if(Centered Sink, Length / 2, Sink Location)

Ideally, this would be the formula for Sink Location parameter.