I'd use a second, hidden timer counting DOWN from 45:00 to 00:00, with an "OnCountdownEnd" trigger setup to start the other clock and bring it on screen.

Your Companion shortcut then starts both 45min timers together.

Maybe here?
https://www.kaylarecord.net

As far as I know you can't have a timer start in negative. Triggers can carry out multiple actions - I'd probably for safety do

1) Reset count up to zero
2) Start count up
3) display count up

Exactly "on overlayIn" trigger to main 45:00 vmix input title timer and then to this vmix input the "oncountdown completed" for the 2nd additional timer

Thanks for all your suggestions guys - i now have it working.

Will def have a look at vmix_soccer_clock, but for the time being I do have a working 'fully vmix' solution.

I need to refine it, so I only have 3 inputs (scoreboard, clock normal time, clock additional time), with basic scripting in place and the use of triggers.

Once I have it sorted (still work in progress, but does work in tests) - I will put in here my final solution, so anyone searching in the future of something similar can see the solution I used, and have that as a starting point

Never dealt with Pages before - but I think that is a great idea..... Need to work on that. Thanks for the suggestion (and another learning opportunity)

So I have it all working - thanks to everyone who helped.

Page 1.png (19kb) downloaded 32 time(s). Page 2.png (24kb) downloaded 28 time(s). Page 3.png (29kb) downloaded 32 time(s). Page Field Names.png (25kb) downloaded 31 time(s).

GTDesigner - see above for screenshots
Transition in – everything hidden
Page 1 – ScoreBoard Only
Page 2 – ScoreBoard plus Normal Timer
Page 3 – ScoreBoard plus Additional Time Timer


5 Shortcuts (streamdeck)
1 – Scoreboard Only ScriptStart ScoreBoardVisible
2 – 1st Half ScriptStart ScoreBoard1stHalf
3 – 2nd Half ScriptStart ScoreBoard2ndHalf
4 – 1st Half Extra Time ScriptStart ScoreBoard1stExtra
5 – 2nd Half Extra Time ScriptStart ScoreBoard2ndExtra

Scripts:
ScoreBoardVisable
Function=OverlayInput1IN&Input=ScoreBoard
Function=SelectIndex&Value=1&input=ScoreBoard

ScoreBoard1stHalf
Function=ChangeCountdown&Input=ScoreBoard&SelectedName=Clock.Text&Value=00%3A00%3A00 (this sets the start of the timer, so 00:00 for 1st Half, 45:00 for 2nd half etc)
Function=SetCountdown&Input=ScoreBoard&SelectedName=Clock.Text&Value=00%3A45%3A00 (this sets the end of the timer, so 45:00 for 1st Half, 90:00 for 2nd half etc)
Function=ChangeCountdown&Input=ScoreBoard&SelectedName=Additional.Text&Value=00%3A00%3A00 (this sets the additional timer start back to 0)
Function=SetCountdown&Input=ScoreBoard&SelectedName=Additional.Text&Value=00%3A55%3A00 (this sets the additional timer end back to 55 - just so it does not set off oncompletion)
Function=SetText&Input=ScoreBoard&SelectedName=Half.Text&Value=45:00+ (this just sets the additional time visible (left side))
Function=StartCountdown&Input=ScoreBoard&SelectedName=Clock.Text (this starts the timer)
Function=OverlayInput1IN&Input=ScoreBoard (this sets the scoreboard input to overlay 1)
Function=SelectIndex&Value=2&input=ScoreBoard (this sets the scoreboard to Page 2 - which is the normal match clock)

Repeated for other halves, with adjustment to time in 1st 2 rows (starting time, ending time eg 45:00 to 90:00
NB 90 mins needs to be 1 hour 30 mins

Scoreboard – Triggers
OnCountdownCompleted selectindex scoreboard value = 3
OnCountdownCompleted ChangeCountdown scoreboard value = 00:00:00 (for additional text)
OnCountdownCompleted StartCountdown scoreboard value = 1 (for additional text)

This selects Page 3 (Additional Time), then sets Additional Timer to 00:00, and then starts that timer

This may not be the most elaborate way of doing this (but significantly better than other options i had originally) - and most 'competent' coders will probably be pulling their hair out! But it works for me, and can give someone looking for something similar ideas of how i done it.