Can a distance parameter be controlled by a list of distances?

[Sahay_R]

Hello all,

I have a family where the geometry needs to have it's distance controlled from a reference plane. This distance needs to be one of four standard values. Short of memorizing the values, how can I set up a formula so that distance A = distance B or C or D or E?

I would rather have this baked into the family itself. I don't believe it can be done with Global Parameters in the project. 

Much appreciated.... in advance.... 

Rina

[SteveKStafford · Accepted solution]

How does this relate to the user placing the family? Does it just vary from type to type or can any type have one of these four values?

You could create a integer parameter that the user enters 1-4. The length can evaluate that parameter to see what it is and return the correct length (see image).

[barthbradley · Accepted solution]

I'd need more info about the family, but my initial thought is Lookup Table.  

[ToanDN · Accepted solution]

- Create a family with 4 types and a Length type parameter, give each type a set distance. Build the geometry in this family.
- Nest it in another family (no geometry), add a Family Type instance parameter (Label).
- Load it in your project and user can select the family and choose one of the 4 length options from a drop-down.

[Sahay_R]

Thank you , gentlemen, @ToanDN  - the attempt is to avoid types, since the distance will vary over instances, possibly more so than the 4 standard distances that I mentioned. @barthbradley I am investigating Lookup Tables as I type. @SteveKStafford  - this is just right! The formula is what I was looking for - thank you!

[Sahay_R]

@barthbradley How do Lookup Tables work? I've got a CSV imported into the family - what next? Correct me if I am wrong - this table seems to lack required info for Lookup Tables to work....

[ToanDN]

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@Sahay_R wrote:

Thank you , gentlemen, @ToanDN  - the attempt is to avoid types, since the distance will vary over instances, possibly more so than the 4 standard distances that I mentioned. @barthbradley I am investigating Lookup Tables as I type. @SteveKStafford  - this is just right! The formula is what I was looking for - thank you!

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Types in the nested family are only a means for the family creator to create the dropdown.  End users do not see types, they only see the drop down list to choose from.

[Sahay_R]

@ToanDN very true. And here is the  rub - I am creating a theater seat family, which needs to have 3 seat width types - which is the easy part. The seat back needs to have a clearance from the floor riser behind it of a certain value. SO - I need to be able to pick the seat type, and then the required clearance (which could be for ANY seat type). So far - I am thinking seat width types, with the clearance driven by the formula earlier suggested by @SteveKStafford - any better suggestions would be appreciated.....

[barthbradley]

So, if the "ClearDist" Parameter Value is 2 7/8", what parameters are to be populated with what values? These are your next columns.  

[ToanDN]

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@Sahay_R wrote:

@ToanDN very true. And here is the  rub - I am creating a theater seat family, which needs to have 3 seat width types - which is the easy part. The seat back needs to have a clearance from the floor riser behind it of a certain value. SO - I need to be able to pick the seat type, and then the required clearance (which could be for ANY seat type). So far - I am thinking seat width types, with the clearance driven by the formula earlier suggested by @SteveKStafford - any better suggestions would be appreciated.....

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Both methods will work.  Using a formula has its simplicity of everything in one family, but you need to clarify with users which Integers (1, 2, 3..) are for which dimensions.  Using a Family Type label has more work up front but it is more descriptive to users (Pick clearance: 6", 10" 14" etc...).

Example file attached.

[Sahay_R]

@ToanDN I will look at this with great interest....

[SteveKStafford]

My blog post describes the technique @ToanDN describes and has a file you can download to reverse engineer.

[weronika.chrzanowskaRYSEB]

@ToanDN I created my family according to your tip and almost everything works perfectly.

The problem which I have is when I load my family in the revit project in my drop box I get not only types of family which I created but all shared generic model family types present in the project. Any idea how to fix this?