Business rule: Add other field value to date?

Question

I'm trying to programmatically set the Due Date field of a custom activity. I want take the value of another date-time field that the users enters and add the value from an integer field. But it seems that I can only select a static value to add using the business rules as shown here:

Is there a way to do it using business rules? Or do I have to use a Javascript instead?

Answer 1

You can use calculated field for these scenarios, but it is not a physical field to store. If you have to store the value, then Javascript or plugin or WF is better.

Business rules are limited in these situations.