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How To Kill A Particle With Id?


ykcosmo

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thx aracid, I have checked your file, and I can't see the ID1 particle is killed by kill pop....I did the same as your example.

may be I make mistakes to see the ID of the particle? how do you see the particle ID?

I have an animation that there is a particle too close to the camera, I want to delete it, only this one. I tried many times but have no idea....

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I know it is a simple question, but I failed to use a kill pop with the rule:$ID==1 when I want to kill the ID1 particle.

You are probably killing ID 1, but the thing that POPs does is reuse IDs. So even though you are killing off ID 1, the particles get reassigned their IDs and another particle will be assigned ID 1. What type of effect are you trying to get?

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The aracid's file works perfectly. The kill pop kills the particle with the ID=1. Another particle borns at the same position of the $ID=1 particle when all the points of the grid have emmited their particle.

And I think POPs don't reuse IDs. $ID is constant, $PT isn't.

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may be I make mistakes to see the ID of the particle? how do you see the particle ID?

The first thing you do is turn on the point display in the viewer.

Find the point number of the point you want to delete this will be $PT.

In order to find the id you need to open up the attribute spreadsheet

and find the id number that corresponds to your point number.

luca

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A quick test looking at the details view/geometry spreadsheet will show that the IDs do not recycle. The point numbers are always changing but IDs stay the same. If the ID changed then there would really be no point in having an ID attribute. Also, there is in fact no particle with an ID of 0. IDs start at 1.

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A quick test looking at the details view/geometry spreadsheet will show that the IDs do not recycle. The point numbers are always changing but IDs stay the same. If the ID changed then there would really be no point in having an ID attribute. Also, there is in fact no particle with an ID of 0. IDs start at 1.

AHHH!!! Yes, of course....my mistake...I was confusing IDs with PTs. When I went into POPs, I wasnt looking at the ID attribute, I was just looking at the left column that has the point number. Sorry for the confusion

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...I had the same problem...

I hade 200 particles... I copied 200 models on them... but the model copied to particle 0 was not able to get its texture... When deleted the "0" was assigned to an other point... I am really confused about IDs and PTs... :(

The solution I had was using the edit SOP to put that stupid 0 point far far away :)...

Very sad... Think about it... a nasty point that causes trouble... sitting alone far away in the X axis :)

Ofcourse I was using a BGEO sequence of the actual particle simulation... so editing was possible...

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  • 3 weeks later...

This is an oldish thread, but what the hell :).

The only real difference between PT and ID is that ID is unique to each particle while PT isn't. So if you have particles that never die and you never kill any, then ID and 'PT+1' will match exactly (ID starts at 1 and PT at 0). If you remove some particles, or some die, then you'll get a mismatch between ID and PT.

The best way to see the ID of a particle currently is using the geometry spreadsheet.

So for the people who are confused, as a rule of thumb you should never do anything with particles that involved $PT, things will get pretty unpredictable if you do. Always use $ID and you'll be fine.

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So for the people who are confused, as a rule of thumb you should never do anything with particles that involved $PT, things will get pretty unpredictable if you do. Always use $ID and you'll be fine.

Unless you're using poppoint() or you're using a point expression to assign a stamp parameter in

the copy sop. I those cases you want to use $PT.

Luca

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