I need help understanding how this moment frame family is constrained.

[Anonymous]

I realize this is a structural family, however my question is about the constrains on the family itself. I thought this forum would have more people who could help out. 

This is the family on RevitCity: http://www.revitcity.com/downloads.php?action=view&object_id=5214

I understand how almost everything is constrained except the height. The high is tied to the reference plane, but I cannot find any constraints on the geometry to the reference plane. If I move the lines of the sweep and extrusion off of the reference plane they still move with the reference plane. There are no constraints or dimensions I can find tied to the lines defining the sweep or extrusion, nor the geometry of the sweep or extrusion. A coworker and I tried recreating it 1:1. Everything functions except the height parameter. 

[Alfredo_Medina]

Maybe you should post the family here, instead of just posting the link. The link requires login to Revitcity to download.

[Anonymous]

Here is the family. I forgot RevitCity required a login.  

[ToanDN]

The top sweep path is constrained to a diagonal plane, which, in turn, is constrained to an intersection of a horizontal and by a vertical planes.

[Alfredo_Medina]

The frame is made of two parts. The part on the left is an sweep. The part on the right is a nested family, which is made in the same way as the part on the left.

The part on the left constrains the height by constraining the endpoints of the lines in the path to the intersection of the reference plane that determines the height, and the diagonal that indicates the slope. The height is controlled by the "Eave Height" parameter.

The part of the right constrains the height by association of the "Eave Height: parameter (in the nested family to the local "Eave Height" parameter in the host.

[Anonymous]

Thats true, however I can move the sweep off of that intersection and it will still move with the reference plane. Additionally, If I delete the dimension on the reference plane and move the plane it does not move with it. It will move with it again if I replace the dimension and parameter. If I use just the dimension and not the parameter only the sweep moves with it. See attached images.

[Anonymous]

I can move all the lines off of this reference plane and they will still move with it. I don't see any way to the sketch lines to the reference plane without the endpoints being on the reference line, or a dimension going from the reference plane to the endpoint. I cannot recreate this family as it appears. I can take a different approach and achieve the same result, but I really want to understand how this was accomplished in this file.

[ToanDN · Accepted solution]

This behavior is similar to what you get when you create a family using an OOTB family with Height parameter presented such as Casework or Door.  

See the screencast.  These lines were drawn without any constraints but moved when the Height changed.  Go figure.

[Anonymous]

Ah ok, the family templates I am used to working with do not behave this way. It is frustrating that things like this are different between family templates. As far as I can tell this is not documented anywhere. Do you know where I can find information on family templates that goes into the differences in behavior like this? 

[ToanDN]

I have no idea about any documentation like that. It's all trials and errors for me.