Having trouble using a mirror mask


So I am trying to create what I figured would be a simple mirror mask so that every other pixel is selected but it is mirrored in the center and thus ‘reverses’ the order.

My example, I have five LED bars each with 10 pixels so a total of 50 pixels. I want to select every other pixel but in the middle ‘flip’ or reverse thus mirroring to the other side. So to the left it would be the odd numbered pixels and to the right it would be the even numbered pixels.

I would assume that a mirror mask of 25 would produce the desired result but it does not. Please see the attached YouTube video


Fan <> Mirror per X to 10
Wave per X = 5

Fan <> Mirror per X to 5
Wave per X to 10


Dummy fixtures can also be patched to affect the FX engine. For example, a less frequent effect by including dummy fixtures. Maybe including a dummy fixture in the group would help.


It doesn’t change the issues if I turn Fan/FX on but I’m not trying to fan an fx.

I will say if I apply an fx using fan fx and pick an appropriate wave multiplier it does a nice job of fanning the effect.


Ok that’s clearer for me now.

What you can try to do, is create your group by selecting from pixel 1 to 25 and from 50 to 26.

You should arrived to get the right mask.

Or as explained by @truthcollins, usage of dummy fixture will help you to get mirror on odd number of fixture (you have even number of pixel but not even number of fixture)


Well normally on something like this what has worked previously is if I have a group of fixtures i.e. 1 - 8 and I want to mirror I would select 1 > 4 + 8 > 5 and it mirrors perfectly.

So I tried 141.1 > 143.5 + 145.10 > 143.6 and it gives me the same result.

I will try the 141.1 > 143.5 + 143.6 > 145.140 and see what happens. I did not try this yesterday.


What would you like to achieve exactly?

If you just mirror by 2 and then press next, the mirror is fine.

Can you detail more please?


Hello Sylvain,

What he was trying to achieve, is this… I did that with 2 simple groups…
The Grouping Tools engine seems to get confused, to the Virtual Master of this profile (10x groups)

Mirrored Odd Even FX


But why would it be confused by the master if the master is not part of the selection?

I could understand if I selected 141.0 - 145.10 it would get confused.

Seems like a bug.

BTW another thing that seems to be odd, maybe related, is that if you enter 141.0 > 145.10 or 141 > 145.10 when you look at the selection order 141.0 (master) gets stuck at the end of the selection order.

I’ve been able to create my groups manually selecting the fixtures I just figured it was worth pointing out this issue because it seems like a bug that needs to be fixed.


As a side note, another observation is if you’re using slice it should be ignoring the master fixture as well. If I type in 141.1 > 145.10 using slice it should be completely ignoring the master fixture yet something is definitely throwing off the math that it’s using to calculate the mask.