Thursday, June 14, 2012

Wall Quirks

Got very busy around here, hence my extended silence. To make matters worse, there’s Euro 2012 now so…while Zach Kron continues to chirp away at funky forms, nodes, divided surfaces and adaptive component families, I think I’m going to continue pointing out the Quirks of Revit WallsTM .

When you unlock the bottom of a wall layer, you can extend it past its bottom constraint (and vice versa for the top). This functionality has been in Revit for as long as I remember. Nowadays we get a lot more control through Parts functionality if we want to fine-tune for panel joints, thickness, extents, etc. Layer unlocking is very handy when trying to rest the base of masonry veneer on a brick ledge or when you want the gypsum board layer to stop below the top of the stud layer for example.

However there is a peculiar condition that we’re presented with when we edit the profile of a wall to create an opening. I totally understand the programming logic of why, but from an architect/builder perspective, this does not make any sense at all. When the profile is edited, the bottom-most horizontal line is still recognized as the base of the wall, so if you edit the Base Extension Distance, you end up with that same extension happening at the “opening head”. And as you might have guessed, the programmer and I just don’t see eye to eye on this one as I don’t believe it should behave this way. Anyone else agree?

Unlocked Layers

So in an effort to outsmart Revit, I inserted an opening instead. As you can see in the middle example above, it seems to solve the issue. However this only works if there is a positive offset value for the opening and as you can see on the right example with the opening having a negative or no base offset, the opening head is messed up once again…#fail3.

By now you’re ready to stop using the unlocked layer functionality; but wait a minute, there is a way (as always!): start an in-place wall family and create an opening in there (Revit will ask you to pick a host).

InPlace wall opening

I know, it shouldn’t be this hard. We see eye to eye on that one.

When working on my first Revit project, I dealt with this same issue only to have it resurface years later while helping another team. It was actually the same exact design scenario: an exterior wall with varying “panel” finishes and continuous stud backup. The team edited the profile of one wall and nested the other in. However when the layers were subsequently unlocked and the masonry lowered to rest on the brick ledge, all head conditions messed up and started overlapping the layers of the nested wall. In such a case, your best option is to not even mess with openings and just embed one wall within another using the Cut tool in plan view, since it’s easier there.

Embedding walls

Now when you need to adjust the size and location of the embedded walls, you won’t have to chase around the project correcting the openings as well. And the unlocked layers won’t give you any heartburn either.



Alex Gore said...

I do agree with you, and thanks for the post.

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