I am trying to put together a filter that will produce a lookahead programme, but does not rely on data from special columns.
The required filter will show;

tasks that start between 7 days before a user input date and a point 21 days past it (now-7 to now+21)

tasks that start between 7 days before a user input date and a point 21 days past it (now-7 to now+21)

Tasks that start more than 7 days prior to the date, and end more than 21 days after it.

this would show all tasks starting, finishing or carrying through the 4 week spread of -7/ +21 days from the user input.

I can manage this using columns, as I can use the "current date" function, from which I can produce the filter. However the filter really needs to be a standalone that works from a user input date due to restrictions I wont go into now.

I know I can use an input ("Date to set as start"?) but can I then use the input throughout, or do I have to put a new value in for each calc?

Thanks all.