I am hoping someone here knows a solution for what I am trying to do.
I have a 32 step sequence. I now want the same sequence with a different sound that will play when I hold fill. So I extend to 64 steps and copy the pattern from 1-32 to 33-64.
I then change the filter cutoff and bit crusher for steps 33-64. I only want steps 1-32 to play except when I hold fill. It should then play the fill instead. What happens is that it plays 1-32, then ignores 33-64 unless I have Fill held.
Thereā two fill modes. Regular fill and fill with a line over it. Regular fill only plays when holding fill, and fill with a line over it only plays when not holding fill.
I havenāt really checked fills out yet on my Elektrons. Wasnāt aware that you could use it the way youāre describing tho? I assumed that fill was limited to creating variations only within the same duration of steps as non-fill? Cool if what youāre trying to do is possible tho, I need to check it out 
Fill is a trig condition. The trig is played only when you press Page button while not being in grid mode.
Together with Pre you can launch a whole serie of different notes.
Un-Fill is the opposite, the notes are not triggered when you press Page.
On a drum machine itās really powerful, it offers some immediate interaction on programmed notes.
On a synth is awesome used on two different chords that you placed on two successive trigs that you made closer with microtiming.
First trig with Fill, following with un-Pre.
My favorite trig condition !
TBH I donāt even know what āpreā refers to here 
Iāve only used condition trigs for basic stuff on my AK so far and havenāt really studied up/experimented with them beyond simple āpercentageā style variation. And have never even used Fill on OT 
will do asap!
So itās possible to do what OP is asking for and use Fill to trigger entirely different sequencer steps? Like a sequence plays steps 1-32 in a loop when ānormalā, then when press Fill it plays steps 33-64 in a loop? If so then I totally missed that that possibility was available!
You gotta hold the button =)
It canāt do that. The pattern length is fixed, what you do within is all you can play with (plus, itās not on the OT at all btw)
Fill is close to OT one shot trigs.
But not available on OT.
Pre is a condition that let the note be played only if precedent condition was satisfied.
Un-Pre : note is not trigger if previous condition is satisfied.
Itās fun to use with steps programmed with different retrig rates as wellā¦
Welcome to a whole new level 
Nope, you canāt affect the way a sequence progresses; you canāt tell the DT to just play steps 1-32 until you press a key, and then play 33-64. You can only affect which trigs get played in your sequence, be it 32 or 64 steps long.
Tip: you can use microtiming to shift a trig practically on top of the preceding one. Then set trig condition to FILL on that trig. Then when you press fill, the note gets replaced with your microtimed note. So a trig on step 12, and another on 13, micro-timed as far back as it goes, and trig cond to FILL on that one.
if you want to play alternate notes you need to have an empty trig either side of the note u want to replace.
place a trig an adjacent space (or copy n paste trig and change filter etc in opās case) and microtime it to play at the same time as the original trig beside it.
change both the original and adjacent trigs trig-conditions to opposite values (like non-fill and fill for example).
then those 2 notes will play alternately.
thatās a basic example which you can elaborate on but for fills youāre sorta limited to having to have empty trigs next to the original notes.
if you have a 64 step sequence n only want the first 32 to play most of the time you may have to have the 2 parts in separate patterns and switch by hand when you need the 2nd 32.
thatās another way.
edit: I sorta repeated what Josker said but I was busy writing mi post when he was posting his. 
Great minds, sir. 
Wow. Now that is thinking outside the box. I believe this will totally work with what I am trying to do.
A big thanks to everyone for replying. I was shocked to see so many replies. Another quick question. If I need 128 steps for a note progression, is there a way to extend past 64 steps for a track?
It would be lovely if the pressing of fill let you double load samples on the āfilledā tracks, so that way the page button could trigger a whole new set of samples but still on the same pattern.
I think in general that a fill button trig condition would be a huge benefit for A/B settings of the same step. So if hold the step button along with Fill button you would get an alternate setting per step. So if you wanted a different sample or filter adjustment for the same pattern you could do that.
agreed. it should be the DT āfaderā of sorts.
my brain hurts trying to remember where all the samples are trigged already, nevermind an A/B layer lol
i think after a few weeks that problem will fade. I used to have that issue but now I manuver the DT with ease (for the most part LOL)
yeh iām getting there
It would be pretty simple. You currently over ride a step by holding the step button down and adjusting a value. If you hold the Fill button down and a step you would have the alternate setting that would trigger if you are holding the Fill button. It would be very simple. No need to set micro adjustment triggers.
Now each step could have a different setting ontop of the override.
When I wanted to do 128 steps i cheated by doing 64 steps but having a second melody line that only triggered on the second time around (Trig condition 2:2). This only works if you have the space in your steps to put trigs in next to trigs playing the first time around and shift them with there micro timing, or you can use a second track, set the first one to condition 1:2 and the second one to 2:2 or NEI with a line over it.