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Jostein

popevent in other popnets?

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I am creating the simulation of a wall being shot to pieces - and I am using (at the moment) 3 different pop-systems to simulate: dust, pebbles and larger chunks .. however, I would like to texture these systems differently .. .and the only way I know of how to do this, is putting the pop-systems into separates networks. If you guys know of a better method, please let me know.. :-)

But .. anyway .. is it possible to reference popevents from .. let's say from popnet1 into popnet2 ? Or do I have to create an attrib POP and do it this way? (which should work fine, I guess)

Cheers,

Jostein.

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Hi Jostein,

One thing that you might want to be careful with having multiple systems is in regard to the whether the particles are going to die before the end of the animation. If they live through the entire range, it might be easier. Although you could you popevent() and specify directly the location of another popnet, I think it might be better to shuffle a particular value to an attribute and check the attribute afterward.

I am not too sure, tho... :( I hardly use popeven() personally, as I personally tend to shuffle things into an attribute.

Curious, could you have used any kind of hit attribute to activate your other system?

Thanks!

A

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That's what I am trying to do, basically .. I am now using an attribute POP with an if-statement checking $HITTIME > -1 (generating a true if $hittime has been set) - but I am having problems transferring the attribute into my other popnet... any clues?

cheers,

jostein.

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Hey Jostein,

After you have shuffle things into an attribute, have you looked into the AttribTransfer POP to transfer your attribute over from popnet1->popnet2? The AttribTransfer is a pretty niffty tool. :)

HTH,

Alex

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Cheers, mate! Didn't know about that one... btw: I tried using it - and was a bit puzzled by it - why do I have to select groups? Wouldn't it be sufficient to just select the attributes I would like to transfer? :blink:

Anyway .. I tried to transfer my $HITTIME attribute - and created a new group in my popnet2 consisting of all the points .. but .. not working... hmm ...

Ahh.. .just found out that Houdini 6.5 has an attribtransferPOP .. and I am using Houdini 6.1.208 ... probably have to check that one then? :lol:

cheers, jostein.

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Hey there,

Yeah, AttribTransfer POP is new in 6.5/7, I believe. It's great.

As I am looking into the popevent() and poppoint(), I just realised that you can't steal attribute information from another, seperate particle system. point() won't work either (or so I believe). I guess this make sense. The trouble with stealing attribute information from another system is that, in each system, Houdini has to cook through an entire chain of pop network before giving the result back. Which is why sometimes the POP network doesn't behave the same way as you are expecting it from your understanding of the SOP network. I am not sure if this is to do with SIMD stuff, tho... :unsure: Things do get really icky if you want to do inter-particle system stuff... It's probably best to keep things in one system unless there's not much of intercommunication going on between systems. I am not entirely sure. What's your take on it, Jason? Mario?

By the way, wouldn't it be nice if one can tell Source POP to "act on existing points" instead of having to birth? Just like the Particle SOP can act on exsting point?

Any hope that clearified a bit. I am still thinking...

Alex

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