Pinning an event date to another event date

I would like to be able to pin one event on another. For example - if event a had the absolute end date of 10th January, and event b’s start date set as 3 days after that, it would be the 13th January . Then, if you adjusted event a’s date to the 20th January, event b’s would shift to the 23rd January.

You can do this via the Constraints system, which you can read about here: Dependencies and Constraints - Aeon Timeline 3 Knowledge Base

For event B, you would add a constraint that says Start equals end of event A, with an offset of 3 days.


Perfect! Thank you very much.

A question on how this works.

Event a has the constraint that it starts x years before the end of event b. If the offset is a positive value, the date sets itself so that event a starts x years after the end of event b. Surely if the constraint is that a date is before another, a positive value should work backwards in time.

I have resolved this temporarily by inputting a negative value, but this isn’t intuitive in the whole ‘double negative should be a positive’ vein of thought. It also makes little sense as having the option of a negative value actually negates the requirement of a constraint option to set the start of an event before or after something, you could simply set a date in relation to another with it being a positive or negative value.

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The offset is used to determine the date to use for the constraint, it isn’t related to the constraint itself. The offset is always relative to the timeline, therefore + is to the future and - to the past. It is the offset from the chosen item’s date that is being used in the constraint

eg. if you want to set a constraint where Event A starts X Years Before the end of event B, for event A you would set the options “Start” “equals end of” “Event B” “offset -X years”
This effectively means that the Start of Event A is equal to x years before Event B

I believe you may be confused if you are also using “is before end of” instead of the “equals end of” option? If so, then you just need to think of the offset in relation to the date it is comparing to (eg. end of event B), not the direction that is implied (“eg. before end of”).

There may be cases where you want event A to occur sometime before 1 day after event B. It could finish before event B, or after event B, but no more than 1 day after. This is where using the positive offset makes sense, even thought your starting comparison is “is before end of”. In this situation you would choose for event A “Start” "is before end of " “event B” “offset 1 day”

I hope this makes sense. Let us know if you need more clarification.

I see your thinking here, but it doesn’t make much sense from a functional view.

If you have positive or negative values, then there is no need for before or after, just offset applied to equality.

Or, you have only positive values which work backwards if you select before, and forwards if you select after.

Having both is confusing and may lead to bugs.