I would like to use the model builder to solve OD Cost Matrix in iterations because my origins/destinations FC need to be grouped by attributes. I use the Iterate Feature Selection tool to do so. After performing all OD Cost Matrix in loop, I want to merge all result lines into a single FC and export its table into an excel sheet.

I separate the Iteration part of the process into a subModel with a Collect Values as output:

enter image description here

Then I use the subModel output into another model to do the merge and the export to excel: enter image description here

The subModel seems to run in iteration correctly, but when it's time to merge the output I got these errors:

      ERROR 000622: Failed to execute (Merge). Parameters are not valid.
      ERROR 000400: duplicate input not allowed

Can someone have an idea what is incorrect in my process?

  • 1
    I know this sounds stupid, but if you delete both the submodel and merge from your model, then add them back in again (from scratch, not a copy of what you just deleted), then it may work. After all, this is simply an issue with input/output names correct? At least for myself, this has been a fix in the past.
    – Goldring
    Commented Apr 21, 2016 at 18:14
  • Yes I think its because I save all output with same name, so I'll try using %Value% in the name Commented Apr 21, 2016 at 18:19
  • Good idea. Let us know if that worked
    – Goldring
    Commented Apr 21, 2016 at 18:21
  • See my solution below, maybe you can improve it. Commented Apr 21, 2016 at 18:47

1 Answer 1


The problem was that outputs from iterator in subModel had always the same name ie: "Lines".

My solution is to save every output of subModel in a new FC named with the group by value %Value% using inline variable substitution

You can see the solution in the red square below:

enter image description here

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