Hello.
I have a probme with the Node “FamilyInstance.ByPoint”.
Sometimes it can’t place an instance although the familytypes are the same.
And then i get an error from Revit.
If I use a list individually it works.
Until yesterday i never had problems with this function.
Has someone seen this before?
Does anyone have an idea what the problem could be?
yeah what is it you will insert and on what, looks like a fitting or accesories ?
the objects are selfmade pipes.
allright probably you can share your dyn and a small sample rvt, then i guess i better understand 
Can you translate the error for us? Dynamo is creating the element but Revit is saying it’s invalid for some reason and forcing you to delete them. This is an issue with the specifics of what you’re trying to do, not the Dynamo node.
Unfortunately that’s not possible because it also uses custom nodes that I’m not allowed to share.
But I found out that it’s probably not due to the node.
In the script, two processes run in parallel that have nothing to do with each other.
Both of them use this function.
And as soon as I turn one off, the other works flawlessly.
The script also has been in use for 2 years… the only i have changed is that i have created new familys.
What I have now tested, is that I combine the inputs from both processes, use the node only once and then separate the output again… AND IT WORKS 
the error seems completely random.
The error just says that the instance cannot be created
Every time I change something, even if I just reverse the input lists, it works once.
the second time no more.
After i reverse the input-lists i get the the error with different objects from the lists.
Are you closing and rerunning the graph from scratch each time or are you making changes within the open graph and running again? If it’s the latter, then you likely have element binding that’s breaking with the changes. The first run creates the elements. The second run creates new instances but tries to return the originals which have now been replaced.
We can’t really do much more than guess unless you share the rest of your graph and explain what it is exactly that you’re doing and what “changes” you’re making in the process.
I have found the problem and the solution.
After placing the familyinstances I’m setting a lot of parameters…
In the dynamo script I have changed the parameter names, because of company standards but I didn’t do it in the families.
After I have changed the parameter names in the families too, it works perfectly.
But for me it still makes no sense, that the placement isn’t working because of the setting of parameters afterwards…
