Can't align nested family to reference line

[Anonymous]

Hi,

I'm trying to align a nested family to a reference line in my host family so that it rotates around a certain point.

I've created the reference line in my host family, locked the end point to two reference planes and then gave an angular parameter to the angle between the ref. line and the ref. plane.

I then inserted the nested family and aligned it to the ref. line. The problem is that when I flex the angle, i get a "Constraints not satisfied" error..

What could be wrong?

I'm using a generic face based family for both host and nested families...

Thanks

[Alfredo_Medina · Accepted solution]

You are on the right track. But, it is not necessary to lock the nested family to the reference line in the host. Simply place the nested family using the "workplane" method of placement, instead of "place on face". Since you already put the nested family there, now select it again and find "edit work plane" or "pick new" "workplane", and select the workplane of the reference line. Then with the Move tool you specify the location of the object on its new workplane. It works as if you were just placing an object on a tray. The object doesn't need to be anchored on the tray.

[Anonymous]

That did the trick!

Thanks a lot

[Alfredo_Medina]

Wow, that was quick. I had posted my message just 5 minutes ago!  🙂

[Anonymous]

Hello All,

This is my first post.  I'm a long time CAD Designer, but fairly new to Revit (6 months).  I'm having the same problem as the original poster.  I originally did the exact same thing he did by aligning the planes in the nest family to an angled reference line in the host family.  I got the exact same results when I modified the angle parameter.

After I read Alfred_Medinas reply, I thought his advise would fix it.  It didn't.  Now, when I  modify the angle parameter, the refence line does move.  But, the nested family doesn't move with it at all.  I'm new to the laws of Revit. I really don't see why it would move without some sort of alignment to the angled reference line.  I need help baaaaddd.  My hair is too short to pull out (which is even more frustrating).

[YarUnderoaker]

Hello.
I have same problem as mr. tfgoss.
Please, give me advice how to control location of objects which lying at reference line plane.

[Alfredo_Medina]

@Anonymous 

Welcome to the forum, and sorry for the late welcome, and for not seeing this post before. I was away from this forum for almost one year. What I wrote in post # 2 above is correct. But if you are new to Revit, maybe a video will help you to understand that better. See link below.

@YarUnderoaker

Please watch this video in Youtube, which describes 2 methods for rotating elements in Revit families:

https://www.youtube.com/watch?v=3IWum86W-zo

[YarUnderoaker]

Thanks Alfredo.
I find simple solution: move reference planes which lock start point of reference line and place nested family at start point of refline. This method require to calculate location of moving object in global coordinates insteed of refline local system

[Anonymous]

I have a similar question.

I am creating a custom Truss family using the Structural Framing - Complex & Trusses (because I need more than one type of diagonal framing member, which the OOTB Truss families don't allow). I am trying to make each Truss Panel have a variable width, which requires the diagonal member to rotate in the plane. I have tried a similar way to that described above. I have a reference Plane for the Top Chord and Bottom Chord locations, and I have reference lines for the web member locations. Everything works fine when I only have reference lines - the vertical reference lines are held in place by the panel width parameters (SS and E1), and the diagonals automatically snap to the correct angles as I change either the "Height" or "SS" or "E1" Parameters.

However, I then try to create a parametric framing member using Create>Component, align it to the diagonal reference line, and lock the alignment. Then when I change either the Height or the SS or E1 dimensions, it will say that "Constraints are not Satisfies" and require that I remove the alignment lock. After I remove the alignment lock the framing member is at it's original angle instead of where it should be.

Any help would be greatly appreciated, thanks!

[Sahay_R]

The component that you have created - can you associate its length parameter with that of the diagonal line you have aligned it to?

All else failing, please do share the family!

[Anonymous]

Here it is. Try to change the Height or "SS" value so that the PL 1x1 stays in formation. Thanks!

[Anonymous]

I think an issue might be that the framing member will set "Start attachment level reference" to "Ref. Level" sometimes by itself. When this happens, it locks the elevation of the starting point of the framing member. 

Is there a way I can make it so that it never sets the start attachment level reference?

[Sahay_R]

Try this

[Anonymous]

Thanks! Almost... It works when changing the "Height" but not the "SS" parameter. 

[Anonymous]

Thanks! Almost... It works when changing the Height, but not the SS parameter. 😕 so weird

[ToanDN]

@Anonymous

Can you use the OOTB truss template, build the typical members using proper tools (chords and web), and build the non-typical member as sweep with steel profile along reference lines?

Oh never mind, I realized you cannot create any sort of in-place model in a truss template.

How about create two truss families with the same parameters.  Truss A contains chords and half of the web.  Truss B contains the other half of the web.  Place them in the same place in the project and assign different structural members to them.

[Anonymous]

Not a bad idea! I'll have to give it a shot tomorrow. 

[Anonymous]

Hello,

I'm having the same problem as the original poster but this is a Detail Component family which does not have the option to place on a workplane.  This is a component to show a bifold door that i would like to flex the Swing Angle.  Family attached if anyone can help.  Thanks.

[MuirEng]

I am having the same problem as the last post, unanswered. I have a nested family hosted on the reference plane and I want to rotate it around the z axis. It should be a simple matter to lock a reference line aligned to the y-axis in the nested family to a rotating reference line in the hosting family but this generates the dreaded constraints violation error. The nested family is unhosted. I tried setting workplane based on and off. Always vertical is set to off (but really I do want it always vertical, just rotated in some cases). Family attached.

I do not believe the solution of hosting the family to a rotating workplane works in this case, unless I rebuild the family completely. Hoping for hints!

[gsucci]

Yes, nested detail families do not have a plane association, so we cannot use the associate reference line method.

So we are back to the nightmare of Revit multiple angle and linear parameter constraints with a rotating nested family, with nearly unpredictable results when flexing the parameters.

So far, I observed that tabbing the correct reference when aligning the nested family must have some consequence. For example, you can align a strong reference plane, or a piece of geometry (lines) in the family, and the nested family will align or not, or behave differently when flexed.

Also, if there are instance parameters in the nested family, those as well will prevent the alignments from working, meaning that sometimes the family will stretch instead of moving to the correct alignment.  So we need to lock the parameter, or create a new constraint so that the nested family will move instead of stretching.

Also the sequence of locking the constraints seems important, and the fact that the nested family should have its own angle dimension with the angled parameter, and not trying to follow the reference line angle parameter because it will never follow it...

Anyways, any good tips on rotating nested detail families in a detail family?

thank you

regards

gio