Quote from TomberYes, you can do this in three easy steps. In a custom bar group, add a bar for the cooldown you want to see (I tested it on a priest with Psychic Scream, so I created a bar for that spell) and enable Show When Ready. The bar now shows all the time.
Next, create a new condition and, on the Tests tab, select All Cooldowns, enable the test, enter the spell name, and set the Time Left test to "Less Than 10.0 Seconds" (at the top of the tab, the Summary for my test had two lines: Condition Name: Psychic Scream! and All Cooldowns: "Psychic Scream", Less Than 10.0 Seconds). This condition is true both when the spell's cooldown has less than 10.0 seconds remaining and when the spell is off cooldown.
Finally, go back to the custom bar group entry for the cooldown and under Special Effects enable Hide and False with the Hide Condition set to the condition you just created. Now the bar is visible only when that condition is true, which means you get a ready bar and the last few seconds of the cooldown, as requested.
I was doing this before to create a sort of combo icon that displays the buff time when I have something active, then the cooldown once the buff is gone, and then a ready icon for when it is not on cooldown. However, as a DK, cooldowns on rune abilities can be tricky, specifically, Pillar of Frost. This can be on cooldown 2 ways, one if the abilitiy was used in the last 60s, and one if you have no frost runes. Now if I create the standard cooldown bar from the setup tab, it correctly shows the cooldown if it has been used the last 60s, and disregards any cooldown that appears on the ability if I don't have any frost runes available. I have gone through every possible condition and setting to get this behavior in a custom bar, but every way I've tried assumes the ability is on cooldown when I have no frost runes available as well.
How do I get Pillar of Frost to show as off cooldown similar to the default cooldown bars, ignoring runes, is my basic question?