topic Re: Unable to create a nested family with 3 objects in Revit Architecture Forum

Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 11:08:16 GMT

I want to create a trestle/ tower look a like in which I want to flex the attributes like plan length and width and height of the model when ever i want to. I am new to this platform and fortunately I could make up to the columns and gusset plates perfectly as per the requirement. But I am not able to place the braces so that they move along with the columns and gussets whenever the dimensions are changed.Any idea how to go about it, anyone? Kindly help. I am struck with this from yesterday. Even though I gave all the formulas correct in the host file, the brace is not taking that value. It seems that it is constrained to something in its file. Also I want to know isn't it possible to lock an object to any reference plane we want? That is like a basic requirement which should be provided in REVIT families to make the job easier. I thought of creating a reference plane along the slant direction and constrain the length of the brace or the angle of the plane but in both ways I am only able to constrain the plane but not the brace. In the file I attached I could only flex vertical projection but not horizontal projection that too in its in own file. When it comes to host, something else happens. Please suggest some way to go about this.

Re: Unable to create a nested family with 3 objects

dzanta — Thu, 03 Jan 2019 13:28:28 GMT

Rule of thumb when building families that will help you....

Host physical objects on Reference Planes and Lines. Align and lock the sides/ends where necessary

Parameterized dimensions control the placement of Reference Planes and Lines which in turn drive the movement of the physical objects

From what I can gather from your files, your physical geometry isn't drawn with Reference Planes that act as the skeletal system, which causes inconsistencies in flexing the geometry.

The angled brace needs to be hosted on a Reference Line such that the end of the brace is aligned and locked to the end of the Reference Line. The Reference Line endpoint that attaches to the gusset plate needs to be locked as well.

There needs to be Reference Plans that define this Reference Line endpoint location and locked so it can move in all 4 directions and even angularly when the frame is flexed

I have Revit 2019, not an older version.

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 13:40:21 GMT

I have not seen any option to lock objects to reference planes. I will install 2019 to check there if any option is available and get back to you 🙂

Re: Unable to create a nested family with 3 objects

dzanta — Thu, 03 Jan 2019 13:47:35 GMT

when I say "lock objects to reference planes" what I mean is that when you are creating the object (i.e. boolean operation of extrude for a simple rectangular extrusion), the magenta lines of the sketch need to be aligned and locked to their respective work planes before you get out of sketch mode.

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 13:59:17 GMT

I understand what you are trying to say. I did use that locking option when i created the 4 columns and gusset plates. As you can see in the revit model i have sent, if you change the plan width and length, then tend to change exactly as changed. Also for a basic rectangle extrusion, those lock are visible but when i am trying to create an assembly using already existing rfa files of shs sections, i am not able to see that locking option to reference planes especially for the brace I mentioned.

Re: Unable to create a nested family with 3 objects

dzanta — Thu, 03 Jan 2019 14:03:11 GMT

sorry....by comments were not clear.

yes your gusset plates and frame are drawn ok.

the bracing angle member should be hosted by a Reference Line. The reference line needs to have the endpoint at the gusset place locked via the endpoint. You will need to use the Tab key to cycle thru so Revit can see this point. The Reference endpoint needs to have it's location (horizontal/vertical) locked based upon reference planes that define the location of the framing.

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 14:15:27 GMT

First of all, no need of sorry. You are trying to help.

I did not know about that Tab key thing. I will try that. Right now, I have started installing 2019 in my PC. Oops..

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 16:59:42 GMT

Couldnt install Revit 2019 but got 2018 at least.

I tried what you said, that is, using tab key to pick points and align to lock the column to reference line as well as the reference line end points to the gusset plates. Still there is an issue. I am attaching the screen shots of the issue. When i change length and width from 2400 to 1800, its not behaving as i want.

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 17:02:08 GMT

sorry i have attached the old file.

Re: Unable to create a nested family with 3 objects

dzanta — Thu, 03 Jan 2019 17:52:38 GMT

Your main framing family was drawn properly such that the objects are aligned and locked to reference planes for flexing. I have fixed this file and it is attached (Framing Family Fixed.rfa). You will also see the Reference Lines drawn correctly so they are anchored at the endpoints so when you flex the frame either in width, height, or length...the reference lines will flex properly.

You now just need to nest the bracing family into this file and align and lock the ends accordingly.

Here are some youtube videos I made regarding building families and the basics of how structure and relationships work...

https://www.youtube.com/watch?v=T8gM35V_nI4

https://www.youtube.com/watch?v=ziNgE5F4rH0

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 19:53:57 GMT

I am really sorry to say that it is not working again. As said earlier, the system is working fine to flex all three dimensions without the braces even in the file that i have sent you. Problem persists when the braces are introduced. I tried introducing braces in the file you have sent too. Same issue repeats. I still don't understand if there is anything that I am missing any point that you are trying to point out.

As you can see I tried introducing 1 brace and tried to change the dimensions, then it wont flex the way we want

By the way, I have installed Revit 2019 too now to access your file.

Re: Unable to create a nested family with 3 objects

dzanta — Thu, 03 Jan 2019 20:21:12 GMT

my apologies...

I must be tired

the only thing left to do is have the bracing hosted by the angled reference lines and locked at the ends so when you flex the frame it will work.

I am looking into how to lock/nest the bracing on to a reference line....

be back asap

also

see if you can request help from @ToanDN He is a great resource and usually solves my problems when I get stuck

Here are my files in 2019 format to continue solving the issue

Re: Unable to create a nested family with 3 objects

Anonymous — Thu, 03 Jan 2019 20:34:48 GMT

yes, i think you exactly understood what I am looking for from the beginning. Anyway, I learnt some new things throughout the interaction.

Thanks for the reference and I will keep you posted if I get something.

Re: Unable to create a nested family with 3 objects

dzanta — Fri, 04 Jan 2019 14:23:29 GMT

So after several attempts, I got it to work.

Create the Reference Lines that act as the skeleton framework for the bracing

Ensure the ends of the Reference Lines are aligned and locked to the appropriate Reference Plan intersections

Set your current Reference Plan to the horizontal plan of the Reference Line

Add your bracing member to that horizontal reference plane of the reference line

Align and lock the ends of the bracing to the endpoints of the Reference Lines

Flex to ensure it works for you.

I have attached my working file for you to study and continue to use....

Hope this helps

Re: Unable to create a nested family with 3 objects

Anonymous — Fri, 04 Jan 2019 16:21:39 GMT

Sorry to say, I have already tried that. It does not work. As you can see in the file, if you try to flex the 3 dimensions (i.e., 3000,2500,3500 instead of 2700,3000,3304.7) it shows an error that the constraints are not satisfied. To tell you, I have also tried taking this brace into a new family and gave family parameters so that I can flex its length and angle accordingly. And then I loaded that into the main framing assembly and associated the diagonal length by giving a formula using the plan dimensions of the main frame. But still REVIT is not recognizing it.

Re: Unable to create a nested family with 3 objects

ToanDN — Fri, 04 Jan 2019 19:16:58 GMT

do not use any structural family as a nested family. it will break when you load in project, even it works in the family environment