Nulls from Face References

Hi All,

I would like to avoid these nulls… I can’t see any reason for them…

@Kulkul I would be very grateful for any suggestions :slight_smile:

Thanks a lot,


wallnulls.dyn (4.3 KB)
wallnulls.rvt (1.9 MB)


when you have 2 intersecting walls, by default they are automatically joined, that means that one is trimmed by the other one. That’s why one solid has 6 faces (as it should be) and the other one has 12 faces.

The two inner faces of the trimmed wall are not valid as a reference and that’s why you got an error.

One solution could be to unjoin the walls:

or you can always use List.Clean after the Clockwork node

Hey, thanks for your response :slight_smile:

So if a door ‘trims’ a wall, I get valid references…

But if a wall ‘trims’ a wall is not valid…

I guess that’s just how it is…

As you note, it is a funny thing that 1 wall is randomly deemed the cutting wall and the other isn’t.

I guess that just reinforces that this method of getting references must be supplemented by a 2nd method for getting intersecting wall faces as shown here…

Edit: Insidentally, that method won’t return references of doors :smiley: Only System Families… It’s all fun…!

Back to Python…!



I might be totally wrong, but I think that’s how Revit is designed, it doesn’t depend on Dynamo or Python.

When you make a dimension in Revit of a wall intersected by another wall, you are not taking as a reference the face of the trimmed wall (those 2 surfaces who are giving you “null” value), but the faces of the other wall.

The same is when you have a door or a window. You are not taking as reference the faces of the hole, but the reference planes of the doors/windows (indeed you can get the heigth of the window below the width dimension).

So if you want to replicate this behaviour in Dynamo or Python, you need to use the same references (the faces of the intersecting wall, or the references of the doors/window).

I think that’s right, the issue is the different ways that references can be generated, I’m trying to mix the 2 approaches now, we’ll see how it goes :slight_smile: