Hi,

I have several group of points to which I want to apply different lag values.
For example, for one group : lag = group number * 0.1

Is there a way to do that easily ? The copy chop doesn't seem to be what I'm after.
For now I have several geometry chops, each importing a group and each followed by a lag chop with a different value.

Thanks a lot.

The copy chop copy's samples in time according to trigger events. What you're after is the $C local variable. You'll be able to apply a lag per data channel.

Check out the tutorial video on CHOPs I think I used a $C with a lag on it.

If you want to actually use point groups .. you'd have to come up with a more creative way to apply the data. For instance, maybe actually apply a uniform lag operation in CHOPs, and then copy stamp the CHOP's parameters on the SOPs level as it's being read into a for-each or copy sop. There might be ways to do this with the expression CHOP as well by using an auxillary attribute (which corresponds to pt group) to blend the info on the transform channels

Thanks for the answers.
I was aware of the $C variable, but it's not easy to use in this case since I want the same lag on a group of points (=channels).

I tried using an auxiliary attribute : a vector attribute called lag in which I entered the values I wanted by hand, and then in the lag chop I tried (I have 72 points in my geometry) : 0.1*ic(0,$C+72*3,$I) but it has no effect.

I tried it in an expression chop and it returns the value I want. Does that mean I can't use ic() expressions in other chops than the expressions chop ?

Finally I tried using only an expression chop with ic(0,$C,$I-1*ic(0,($C+72*3),0)) to use my lag attribute to delay the channels, and it works this time, but it's less nice than the lag chop, which acts on the amplitude too.

I guess I can push it a bit further and redo the lag chop in the expression chop, but it would be nice if all chops supported the ic() expression.

I remember the posts where you requested python chops, and I think chops could use a bit of polishing to be more powerful Still, nice to have them!

By the way, do you know when your ebook will be available ? I'm quite interested.

yeah maybe try to redu the lag .. the oc() expression might be very useful for that, where you'd gather the output channel for recursive operations.

(very very soon :wink: )