How to substract days to a due date?

[Emilie_Ouellette]

Hi, 

First of all sorry if my english is not good, this is not my first language. I apologize.

My problem is that i want to custom a pattern with the due dates. I work in showbusiness and we work backward for everything. 

For exemple, let's say we have a show that will be played on march 14th. I have my due date and i know that 2 weeks before the show, i need to set-up a practice. And 4 weeks before the show, i need to buy costumes. And on, and on, and on.

So i was trying to use butler to set-up rules that can allow to set-up dates in the custom field date from the due date moving backward, but it seems impossible.

Is it even possible?

Thank you very much!

[Ludo]

Hi @Emilie_Ouellette 

Maybe, you can use this method : 

Add a parentcard which contains the final due date (14 mars). 

Add all other cards in a other list "Todo" with a custom field "mydate"

Trigger : move the parentcard in list "Todo"

Associate to this trigger actions like 

• collect all cards in list "Todo" into linked items in checklist "Todo"
• It allows to link the triggercard with all cards in the specified list
• for each card linked from an item in checklist "Todo",  set custom field "mydate" to "{triggercardduedate}"
• It allows to propagate final due date to all cards in the specified list.

Trigger : Set for all cards custom field "mydelay"  in weeks number 

Associate to this trigger action like

• set due on the date in custom field "mydate" minus {{%mydelay}} weeks
• It allows to calculate due date for each card in the specified list

https://help.trello.com/article/1067-using-the-custom-fields-power-up

https://help.trello.com/article/1160-custom-field-variables

Note : if the cards and delays are already set, just use the first trigger and merge the 2 actions blocks