Hi
1 Qus:
I make CHOP–>Geomtry node to display point array `s transfporm, but I don`t know how to offset or change every point animation by some rules, like offset frame by $PT (not offset all point`s frame global).

2 Qus:
I want quote other point node`s info in current point node by some rules, like chf(“/obj/geo1/point1/tx”,$F-3) ,but it return 0 ,I don`t know how to do ?

look at my file, and please help me thank you

1. I don't really get what you are trying to do. If you want to offset the X value of the geometry of point 1, by 1, why not use the point SOP? I just don't get the problem.

2. You don't want ch(), you want the point function. You want to grab the geometry value of the point sop, while ch() is used for getting the animated channel value. So the expression in point2 should be
point(“../point1”, $PT, “P”, 0)
point(“../point1”, $PT, “P”, 1)
point(“../point1”, $PT, “P”, 2)
for X Y and Z respectively

1: I didn`t want to change point`s position, just every point`s animation time, like the point which $PT%2==0 , offset there animation time 1 by 1 , in chop some node like delay can global offset all the input point animation time by some step,but I want offset input point`s animation time 1 by 1 (or other rules)

2: I want quote some sop`s point position by 2 second ago ,
some Exp function like chf() can quote other sop`s info by specify time, but if I do : chf(point (“…/point1”, 12, “P”,0) , $F-2), it return wrong value,

For question, two you could use a trail SOP with the trail length set to 2 (default) and the trail increment set to the frame offset you want to query. So for two seconds you would set this to 48 assuming 24 frames per second. Then append a delete SOP and using “Delete by Range” set the start/end to 0 and ($N/2)-1 respectively. Also set Select _ of _ to 1 and 1. That will leave you with the object as it was 48 frames ago and you can now query the points in a point SOP with point expressions:

point(“../delete1”, $PT, “P”, 0)
point(“../delete1”, $PT, “P”, 1)
point(“../delete1”, $PT, “P”, 2)

An alternative way is to write the geometry you want to reference to disk and then read back in with an expression that gets the earlier frames you want to query.

could you give me one file example? I couldn`t` understand clear

thank you !!

is there have some node in CHOP use for offset pre-point animation ?

Try this, it shows two ways one with chops and one with the trail sop.

thanks for 2 Qus!!!!!!!
but the 1 Qus, how could offset pre- point animation time 1 by 1 or by other rules ? shift or delay node could offset all input point motion time by uniform step, but I want offset input point animation time by different
step ?like first number point motion time is 1-30 frame, second point motion time is 4-33 frame,third point motion time is 7-36 frame……..how to do ?

Sorry I didn't realise quite what you wanted. I've modified the file and added a third option that offsets each point by an expression using chopf in a point sop. Let me now if this will work for you. I've driven the offset with an expression but that expression could reference another graph to give you manual control over each points offset.

thank you !!!!!!!!!!!!! haha !!!!!

but I want know , Why chf(point (“…/point1”, 12, “P”,0) , $F-2) return wrong value ,but chopf(“….”) will return the right value ?

chf will only read an animation channel, the point function is basically reading an attribute, in this case the attribute P or position, so you are trying to mix methods.
Chopf is similar in that it reads from a channel but in this case we have used chops to turn an attribute, P, into a chop channel first before we try and reference it.