Can't ad family parameter

[Anonymous]

I am in the process of creating a family, for a facade-system element (A parabolic steel fin).

All it is, is an extrusion from a sketch, but when i add a instance parameter for height, i get this error message: 

 "The constraints of the sketch defining the highlighted element cannot be satisfied."

It happens regardless of whether the witness line i label, is to the top of the extruded element or a ref plane. 

If the constrains of the sketch can't be satisfied how am i able to finish the sketch and create the extrusion in the first place?

I am using 2017.2

Has anyone experienced similar errors?  

- I attached the family file

[L.Maas]

Look at the reference plane...it is pinned.

[Anonymous]

The issue persists regardless of whether there is ref plane at all, so that can't really be the culprit

[L.Maas · Accepted solution]

Sorry, did not check carefully, was running out of the office.

Seems indeed like a small bug. No clear cause why this is happening

What you can do is slightly remodel the extrusion.

In this case I split the lines at the reference plane. After that I mirrored the bottom part to the top.

After that adding a family parameter could be done without issues (I used Revit 2019).

[Anonymous]

That makes sense, to snuff out inaccuracies - The outline was pick lined from a DWG. 

Thanks a bunch! 

[Anonymous]

Your extrusion profile is not constrained.  I suggest creating a profile then loading it in then create it as a sweep.

[Anonymous]

The thing is they are suppose to represent parabolic properties, which i might have to illustrate somehow later. 

A family lends me more options in that regard than a component.