Creating an secondary due date a custom fields value days before the regular due date

[Stefan]

I tried multiple ways to get what I wanted but always failed in some other way

I want to set up a card with a due date and a custom field set to a number. I then want to either use a card button or a detect a move to a different list

I wanted to try the following :

•  On move / button press - set date custom field "Date" to {cardduedate}-{{%"Field"}}
  
  => I'm only able to select a time frame to move it by 
•  After that I tried to replace the custom field with a start date
  On move / button press - set start date to  {cardduedate}-{{%"Field"}}
  
  => can't use {cardduedate} as it will only allow custom fields to be used here
•  the last thing I tried was to remove the need for the extra due date by edit the Calender Commands to include the calculation each time 
  
  move each card due in less than {{%"Field"}} days to list
  
  => I get an error CANT_PARSE_COMMAND
  

At this point I'm kinda stumped and I would like to get some ideas form you 

PS: I'm not using "Field" as my custom field I just needed a dummy name 

[Garrett · Accepted solution]

Hey @Stefan 

You're quite close to having this set up, but there's one trick you'll need to do, to make this work.

Currently setting a date field doesn't allow for that variable manipulation, so you'll need to use a different option in Butler. Fortunately, you can manually enter the name of the Date field and use a variable as the value.

With that, and some arithmetic formatting, you can get the other field to subtract that set number of days as well.

Here's the action in Butler:

Also, here's the formatting after it's added to the command:

Give that a try and let me know how it goes!

[Stefan]

Thank you very much for helping me with my problem, everything works great now.

I would never have tried to use the "set custom field xxx to" because it wouldn't allow to pick it out of the list. 

I must say that was a bit confusing. Was there something about that on the help page and I just missed it or is it a kinda secret feature ?

[Garrett]

It's not specifically called out in a help doc, but I'll let the team know we should consider adding some clarification that it can be used in that way.

[tkelly]

Bringing back this topic.  When I tried this method, I get the errror:

Couldn't find a Custom Field called "Date" in card https://trello.com/c/ixxx. Please make sure that the Custom Field exists with that exact name.

Any other ideas?