Is there a way I can make a tool (in ModelBuilder) that will automatically set fields to a certain value?

For example:

I manually select a bunch of polygons in ArcMap, run a query on the selected polygons, and multiple fields are updated with the desired value.

1 Answer 1


You want to make use of the Calculate Field tool. If you're unsure about the expression, there are a lot of examples in the help.

Taking your question at face value: you don't need ModelBuilder. You just need to run the Calculate Field tool to update some fields. ModelBuilder is good for chaining tools together to make a workflow. (Maybe there is more to your question than you've said....)

Keep in mind that a model tool (almost any created/singular tool) will act against a selection and only the selection. Eg. You have 10 polygons in your featureclass. Within ArcMap you select 5 of them and run your Model-Calc tool. Only those 5 selected will be calculated (updated).

  • It is also worth mentioning that inversely if there is NO selection then the tools will process all features so one can very easily overwrite their valuable data when they intended to update just a selection, I know this I've done it! :) So I would use a get count tool as a precondition to any updates via field calculate.
    – Hornbydd
    Nov 6, 2018 at 9:58

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