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chaser does not work as expected when triggering sequences for fx

Posted: Tue Aug 23, 2022 12:03 am
by fedemgh
Hi everyone!
I have a question about how to create effects within a cue list. I've been searching this forum and can't find an explanation. I don't know if this is an issue or a bug, or my lack of knowledge.

Imagine that I want to create a strobe effect, and I want its intensity to go up little by little after the previous scene. let's say enter in 2 seconds. in such a way that the strobe effect reaches its maximum intensity after 2 seconds:

What I would try to do is create a sequence with two steps:
1-light channel on 100%, fade-in 0ms, hold 1s, fade-out 0ms
2-same channel off, fade-in 0ms, hold 1s, fade-out 0ms
I would then add the sequence to a chaser step with a 2 second fade in.

well... what actually happens is that when i trigger the effect inside the cue list, strange things happen with the strobe fade times.

I made a similar file with an RGB light so you can better understand what I'm saying....

If there is a way to do what I'm thinking, I apologize for my ignorance, and would appreciate any help.

Thank you!

PS: I'm using version 4.12.5 on windows

Re: chaser does not work as expected when triggering sequences for fx

Posted: Tue Aug 23, 2022 1:55 pm
by GGGss
A tricky one ...
Fading on alternating intensities does not work. Somehow understandable. (HTP and LTP behavior and internal calculations)
A solution could be that the strobe chaser is put inside a frame with a submaster slider also inside that frame.
When you fire the strobe chaser, the submaster will limit the amount of intensity coming out.

The way you automate this submaster (fade-in for 2 seconds) could be achieved by a loopback channel bound to the submaster slider.
For the 'swelling' strobe function to look nice, in my experience, you cannot use a linear curve for the submaster fade-in. An exponential curve will look that much nicer on stage. So a channel modifier applied to the loopback channel will do the trick here.

Re: chaser does not work as expected when triggering sequences for fx

Posted: Wed Aug 24, 2022 3:10 am
by mlohrey
This is has been a problem with QLC+ for a long time. You will find a number of posts describing the problem in the forum. Basically, the fade in/out times in the cue list are applied to the individual step's fade in/out times in the sequence (or other cuelists) rather than the whole effect. So in your case, the strobe step is trying to fade up in 4 sec but after 200ms it then tries to fade out over 2 seconds. This is not possible of course because each step takes 200ms. So the flash never reaches either full or zero intensity. Thus the error you see.

It must be a difficult thing to program as it was identified some time ago.

In the end, for theatre shows I sometimes do, where the ability to fade effects in or out is important, I moved over to MagicQ. It handles this this particular effect without trouble. He is an example in MagicQ. A basic dimmer effect with a 10 sec fade in and then 5 second fade out.
https://youtu.be/uAhymL6Jfkc

I love QLC+ and use it for many other things, just not theatre shows when I need this to work.

Re: chaser does not work as expected when triggering sequences for fx

Posted: Wed Aug 24, 2022 6:40 pm
by fedemgh
Thank for the coments!!!
mlohrey wrote: Wed Aug 24, 2022 3:10 am It must be a difficult thing to program as it was identified some time ago....
that's what i suspected.... but is strange, because when you yust trigger the sequence with a fader or a knob, what you "fade" is the max intensity of the channels involved, something like @GGGss suggetion... so in my head, this shouldn't be too hard to fix... you just ask the cue list to fade-in (or fade-out) whatever is controlled by the knob/fade, right?

I'm learning MagiQ too, but I like to bet on QLC and open source. :)
GGGss wrote: Tue Aug 23, 2022 1:55 pm The way you automate this submaster (fade-in for 2 seconds) could be achieved by a loopback channel bound to the submaster slider.
You lost me here. :shock:
I'm starting to investigate about loopback right now... thanks!