Invert Ifoutput
To take selection of all channels and fixtures with a dimmer value above zero, except the current selection.
Line 1: Store Group 991
Line 2: Ifoutput 01 Thru
Line 3: Store Group 992
Line 4: Group 992 - 991
Line 5: Delete Group 991 + 992
If the intension is to put those ch/fix at a zero value and then continue with the original selection you can add two lines after line 4.
Line 4b: at 0
Line 4c: group 991
To leave out some ch/fix from the macro, add lines between line 2/3, e.g. - channel 360 - group 66.
