Pull values from sublist, add new values to the same sublist?

[Eric_Boehlke]

The idea is to mimic a calculated value in a sublist as in Revit schedules.

How would I pull two values from a sublist, calculate something, and add that new value to the sublist? Example: divide Area by Length in Wall parameters. So far:

[Vikram_Subbaiah]

[Eric_Boehlke]

I see your logic for a single list. When I run it I only get a simple list from Element.GetParameterValueByName. What am I missing now to get and process a list of lists?

[solamour]

Check the ‘lacing’ of each node in Vikram’s solution

[Eric_Boehlke]

Ah, lacing solved it. Those little icons on the nodes are subtle. Very well done, guys.