Constraints & Automatic Sketch Dimension (was Bug, intended behavior, or)

[ron.sanpedro]

Sunny, Friday afternoon, why am I here moment?

Anyway, if I start a new Window from the Window template, go to the exterior elevation view, start a new solid and pick out a rectangle where the bottom edge is coincident with the Top reference plane, I get a lintel that moves when I change the height parameter. Cool, as expected.
Now I delete that solid and do another that is just floating free, no pick points on any reference planes. And yet, the lintel still moves! I turn on Automatic Sketch Dimensions, click my lintel solid, and I get one that references the Reference Level, not the Top Reference Plane. But the lintel moves with the Top Reference Plane. Not cool!?
If I place a new Reference Plane and don't lock dimension to the Top Plane then I finally get a stable solid. Now it seems to me that if there is an implied relationship between that solid and the Top Ref. Plane then I should see an Automatic Sketch Dimension to that effect. And if I didn't pick any points on a reference plane, then there should be no implied relationship, and my lintel shouldn't move until I lock dimensions.

So, is this a bug, or at least an oversight? Or is this intended behavior that I somehow don't understand? Or is this some greater power saying "Go get on the motorcycle, the weather is too nice for Revit!" ?

Thanks,
Gordon

[dbaldacchino]

Could you post your file?

[whittendesigns]

I was just working on a new garage door family last night and walked away in frustration. I swear it was the same thing you just said. Things were moving when they weren't supposed to be and vice versa.

[crispin.schurr]

I get issues like this all the time in the family editor. My favourite is nesting families and locking nested reference planes to geometry (don't do it if you value your sanity!!).

Personally, I would prefer to have to set any associativity manually in the family editor, than Revit guess what might be best.
If you want the geometry to flex with a reference plane then dimension to it - if you want it to stay put, pin it.

C

[Elmo]

Did you use Extrusion? I have noticed that Extrusion solids tend lock themselves to a nearby referance plane and that was even back in 8.1.

[Steve_Stafford]

Following your description, I get the attached automatic sketch dimensions when I edit the sketch of the solid. ASD's are Revit guessing what is important to you. You can control the behavior when you place your own dimensions. If you do well there won't be any ASD's, no guessing on Revit's part. You can also reposition the ASD's reference in the same way you can with temporary dimensions to tell Revit it guessed wrong. But as you add new geometry Revit may guess again. A simple family can be constrained quite easily with just ASD's but as it gets more complex they are just as likely to break eventually.