How to feed a <none> input?

1

Hi,

I’m trying to set a parameter to none for a Parent View parameter and have failed miserably. See attached the different attempts.

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Any ideas?

Thanks a lot

2

the parameter Is Read Only

3

I was unable to find a way using OOTB nodes, but you can do it within a Python node:

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import clr
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import ElementId
clr.AddReference('RevitServices')
from RevitServices.Persistence import DocumentManager

doc = DocumentManager.Instance.CurrentDBDocument

element = UnwrapElement(IN[0])
name = IN[1]
invalid = ElementId.InvalidElementId

parameter = element.LookupParameter(name)
parameter.Set(invalid)
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4

I’ll give it a shot in a bit. Thanks a lot

5

What am I missing here?

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6

Judging by the error, it looks like View.GetByType is outputting a list of views (or possibly a single view nested in a list). Try this code instead:

import clr
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import ElementId
clr.AddReference('RevitServices')
from RevitServices.Persistence import DocumentManager

doc = DocumentManager.Instance.CurrentDBDocument

elements = UnwrapElement(IN[0])
if not hasattr(elements, '__iter__'):
	elements = [elements]

name = IN[1]
invalid = ElementId.InvalidElementId

for element in elements:
	parameter = element.LookupParameter(name)
	if parameter:
		parameter.Set(invalid)

I’ve also implemented an if statement which ensure that the parameter actually exists so that detail views without a parent view are skipped.

7

Wish my Python chops were good enough to tell, but is it possible there’s a syntax mistake I’m making when copying the code? I still get an error even when trying a single view and not a list of views. I’m feeding a known detail view made with a callout. I get this:
“Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed.
Traceback (most recent call last):
File “”, line 19, in
Exception: Attempt to modify the model outside of transaction.”

8

Oops, I forgot to add a transaction manager. See below:

import clr
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import ElementId
clr.AddReference('RevitServices')
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

doc = DocumentManager.Instance.CurrentDBDocument

elements = UnwrapElement(IN[0])
if not hasattr(elements, '__iter__'):
	elements = [elements]

name = IN[1]
invalid = ElementId.InvalidElementId

TransactionManager.Instance.EnsureInTransaction(doc)
for element in elements:
	parameter = element.LookupParameter(name)
	if parameter:
		parameter.Set(invalid)
TransactionManager.Instance.TransactionTaskDone()
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9

This did the trick! I knew there was something missing!

Thanks a lot man this was YUGE

1 Like