Hi Guys
I am try to extract Z-values (levels) from a list of coordinates. I can see the Z-values in the list, but somehow it still returns an error (Warning: Internal error, please report: Dereferencing a non-pointer (3f47aacd). Any ideas to work around this please?
Thanks
Fennen
Hi Fennen,
It looks like your list has some empty elements . Unless the struture of the list is important, try and flatten it.
Hi Mostafa
Thanks for your suggestion and prompt response. I shall have a look into that. I have had the nodes wired exactly the same in a different scenario and it returned Z-values even with empty lists as shown below.
Hi Fennen,
There’s some geometry and revit related nodes that automatically fail for the whole list if the first item in the list is a null or an empty list. It seems that you’ve stumbled on another one with “Point.Z”. I don’t keep a running list but I did report the issue some time ago here:
https://github.com/DynamoDS/Dynamo/issues/5238
Haven’t heard back since then. You could post a new issue and tag the one above, to check with the dev team if there’s been any progress on the matter.
Hi Mostafa
Thanks. Flatten does return Z-values, but I am interested in keeping the structure of the list.
Hi Dimatar
Thank you for your example. I shall have a go at it and see what happens.
Cheers
Fennen
Hi Dimitar
You’re absolutely right about the first item in the list having a null value, Point.Z fails to give a result. However, knowing this now, I can work around this.
Many thanks.
Fennen
If you’d like to keep the original list structure and still ensure that your graph will work for cases where the first item may be a null value or an empty list, you could route the list through a “List.Map” node. It’ll catch and ignore the initial error:
Dimitar
Thanks for that. It does the trick. 
