Issue with changing length of arrayed group in family

[Anonymous]

Hi,

So I'm trying to make an array group's length to be parametric to the overall width of the family. 

The ends of the joists are locked to the appropriate reference planes (the ones 3" off from the total width reference planes).  

Before doing the array, it works fine when I change the width by both dragging the reference plane or changing the value on the properties window.

But as soon as I make the array and change the width on the properties window, I always get an error with the groups or are forced to remove the constraints. It works fine dragging the reference plane though.

What could be the issue? 

[cbcarch]

Make the Reference Plane a Strong Reference. Try Ungrouping the joists.

Save and Load into Project. See if you can drag with grips.

[Sahay_R]

Create a parameter for number of joists. Create a dimension parameter between two joists. Call it Spacing. Add in a formula Length/number of joists

When you modify the length of the array, the joists will modify accordingly.

[Anonymous]

Thanks for helping out!

I would need the joists to be grouped because the numbers have to change depending on the length of the assembly.

Made the reference planes a strong one but still can't make it to work. 😞 

[Anonymous]

Hi! Thanks for helping out all the time 🙂

Changing the number and spacing of the joists depending on the length of the assembly is no issue for me.

It's when changing the width of the assembly (which is the length of the joists) that I'm having issues with.

It works just fine when I only have 1 joist placed. Changing the width works just fine and there's so errors in having the joist change the length as well.

It's only once I make it into an array group that causes the joists to have issues changing it's length according to the width of the assembly.

[cbcarch]

You might need to get fancy and use a formula to drive the spacing and number of joists based on the Length parameter--similar to a Ladder Family that flexes with Length and adjusts the number of rungs.

[Sahay_R · Accepted solution]

@Anonymous - you're welcome!

Procedure for this array - 

1) Create the joist as a family. Give it a length parameter. Save as Family1 (or whatever)

2) Start a new family. Call it Family2 (or whatever) Insert Family1 into it. 

3) In Family 2 - create a dimension parameter. Associate the length parameter from Family 1

4) Array Family1. When you change the value of the length parameter, all instances of Family1 will change.

Good luck!

[barthbradley]

I think this may be related to how you are appending the array. I think you want to Append to End. That requires a different Array setup to work correctly. Also, is your railing baluster a nested family? 

I would be helpful if you could post the family. 

[ToanDN]

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@Anonymous wrote:

Hi! Thanks for helping out all the time 🙂

Changing the number and spacing of the joists depending on the length of the assembly is no issue for me.

It's when changing the width of the assembly (which is the length of the joists) that I'm having issues with.

It works just fine when I only have 1 joist placed. Changing the width works just fine and there's so errors in having the joist change the length as well.

It's only once I make it into an array group that causes the joists to have issues changing it's length according to the width of the assembly.

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If I recall correctly you need to create to add the second instance, get out of the array command and constrain the second instance properly (both ends in your case), then change the array number to a parameter to finalize the joist system.  If it doesn't work out, share the family.

[barthbradley]

@Anonymous: Ah! Sorry I misunderstood you initially. I know exactly how to correct. The nested baluster family needs to be given a length parameter and that parameter need to be associated to a length parameter in the host. Then you align and lock only ONE end of the baluster. The parameter drives its length. 

Like I said, this would be easier to  show you than tell you. Post your family and I'll show you. 

[Anonymous]

I'm attaching the family file.

Still haven't figured out how to work it out after trying all your options! :'(

So what I'm wanting to do essentially is keep the array formula as is (change number of members according to length of the overall assembly), and have the joists change length according to the width of the overall assembly.

Once the floor joists work, ideally I would like to copy it for the ceiling joists as well.

Any guidance would be super super thankful!!

ps. the file is in Revit 2018.

[barthbradley]

You need to pin your Ref. Plane where the Baluster begins from, in it's family. Nevermind. I see problem now. Structural Framing member. I'll study it further and repost. 

[Sahay_R]

@Anonymous is there some kind of relationship that you would like maintained between Length and Width - you know, like Width is 1/2, 1/3, 3/4 of Length, or is a certain number of feet more or less? Some sample formulas - 

 Width = Length*0.75

Width = Length - 2'

Width = Length/2

OR do you have a condition that, if Length is more or less than a certain value, then Width will be something? In that case - 

Width = IF(Length>10, 17, 12)

Which means that IF Length is greater than 10, the value of Width will be 12, if not it will be 12

[Alfredo_Medina]

@Anonymous

Instead of doing a family with an array of 'joists', do a beam system in the project. 

[barthbradley]

@Anonymous...or model your joist family as a line-based family. I can't make it work with the structural framing family.  

...if you do it as a line-based family, you would then align an lock the family's [static] origin to an origin point in the host, and then associate the family's "Length" parameter to a "Length" parameter in the host. The array would then flex properly.   

[Anonymous]

Thanks for looking into it! 🙂

It also doesn't work when I just create an extrusion within the family and use that to make the array and the length parametric. 😞

[Anonymous]

I don't have specific relationships between the lengths & widths. They are all custom depending on the size of the floor area. 

[Sahay_R]

Then you would be better off leaving the parameters as they are, so that you can manually enter the numbers.

[barthbradley]

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@Anonymous wrote:

Thanks for looking into it! 🙂

It also doesn't work when I just create an extrusion within the family and use that to make the array and the length parametric. 😞

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Let's look at it. Post what you did. 

[ToanDN]

A generic or generic line based should work.  If you want to use a structural framing you are better off with using beam system.