Enabling/disabling parameters based on Conditions/Preconditions in ModelBuilder?

Question

I have been working with ModelBuilder and I am having trouble placing a precondition on an input parameter. However, I may be going about it in the wrong way and may just need a Python script.

My example will be based off of the 'Strip Map Index Features' tool (Cartography Tools --> Data Driven Pages --> SMIF) in ArcMap. When running the tool, the GUI shows a checkbox (Use Page Unit and Scale). There is also another parameter/textbox (Map Scale). The 'Map Scale' text box only becomes active or enabled when the checkbox is checked.

I am trying to recreate this functionality using ModelBuilder and I am not sure how to do so.

• Baltok: So, you want the tool to gray out a parameter input when the checkbox is unchecked, and then to ungray/allow it when it's checked?
• user1898629: Yes, well reverse that. THe checkbox starts out as being unchecked. Once you check it, then the parameter becomes enabled or un-grayed out. When you uncheck the box, the parameter goes back to being grayed out / disabled.

Answer 1

You can add a checkbox that you can use as a precondition in ModelBuilder as follows.

In ModelBuilder - Insert - Create variable - then select "Boolean" - if you then make this a parameter it will appear in the model window as a check box. You can rename it and use it as a precondition to sections of the model.

• user1898629: Thanks for your input, but that part is already understood. I have a parameter that is a boolean that does appear on the model window. My confusion is how to make another parameter enabled/disabled depending on whether that checkbox (boolean parameter) is checked or not.

Answer 2

You have to customize script tool behavior. Take a look at Customizing script tool behavior. But beware, it can be quite frustrating until you get it to work correctly.

• Dylan Warburg: Is it possible to customize tool behavior in this way for Model-Builder tools? I thought this option is only available if the tool is written in a Python script.