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Farmfield

POP Replicate from random id at random frame [SOLVED]

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So when I started migrating to Houdini a couple of months back, I really didn't get into the really simple stuff in POPs because I just didn't think that would be a problem - now it turns out that what I thought would be really simple really isn't very simple at all. or perhaps it is and I'm just too stupid (or too locked into my TP/Pflow thinking) to see it... ;)

 

Lets say I have a couple of particles shooting out from one point and I want to have particles "spawn" of these particles at random frames, inherit the velocity but shift the direction a tad. Final step is just have all points create trails using a POP Replicate to spawn stationary particles - but that part I get fine. Oh, and solutions using VOPs, wrangle nodes etc. isn't an issue, any solution will do. 

 

So we're just talking about creating simple growth pattern, something that is ridiculously simple to do in TP or Pflow in Max. Like this setup I did in TP 1-2 years ago, the secondary growth patterns.

 

 

 

Edited by Farmfield
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Hey again,

 

I tried to set up what you asked for. Hope it matches your ideas. It may not be the most elegant solution, there might be a better way to do this, but I think it works.

 

-> Initial Particles, random spawns of secondary particles which inherit the velocity with a variance of 0,3 0,3 0,3 - including particle trails for everything.

random_growth.hipnc

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Man, I really appreciate your help, but I'm really not a beginner here and these kind of setups are just not what I'm after at all. And if I get to the point where I would be forced to pipe stuff in and out of SOP's, I'd rather just create the setup inside a SOP solver and do the setup manually with add nodes and VOP's to control it - or I'd do it using the L-systems - but as all this is only about me learning the POPs in DOP's context inside and out, I'm only interested in solutions inside DOPs using the POP nodes and the streams.

 

And for you to get an idea where I'm at, I'm currently using POP wrangles and VEX snippets for selecting and grouping particles for spawning, but the problem is it's continuously not doing what it's supposed to and/or doing just that but breaking something down the line. And I have real issues with the streams, same thing again, I do a setup, get it running, do something like add a POP replicate to spawn trails, and the setup just breaks - we are also talking streams breaking other streams without any reason - or none that I can think of, at least - basically, for the first time since I started using it, Houdini just isn't doing what it's supposed to and it's seriously annoying.

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I understand. Maybe some indepth-guru around here can help..hope you get stuff running soon! All the best!

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I understand. Maybe some indepth-guru around here can help..hope you get stuff running soon! All the best!

 

Here's my current setup. It works great until you try to do a secondary spawn and it instantly breaks. Houdini is no fun today. :P

growth.v1.hiplc

Edited by Farmfield

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It's as easy as pflow and tp in this case.  ;)  I think you want to use the reference stream inputs on the pop replicate. It's nice too because it's easier to define different behaviour and such to each stream (note the colors on the trails fading vs the heads maintaining).

 

if.growth.v1.hiplc

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In the end, Scratch had the right approach for this all along - with that said there is of course benefits to keep things in one DOP network sometimes, but if you don't need that, piping POP's into POP's is a fast and simple solution for this setup. A special thanks and apology to Scratch as I had the idea you naturally should keep the complete setup in one DOP, totally missing how well it works doing it as he suggested in his very first post. :D

 

https://vimeo.com/123357428

 

@Ian

 

With that said, huge thanks for the file, it's a great outcome for the question posed, one great approach from Scratch and one explaining file from you on how to work with the streams - something that almost drove me mad the other day, just not having a clue why stuff just stopped working for no apparent reason, well, no I know. Much appreciated. :D

Edited by Farmfield

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Yeah there's always more than one solution to the same problem. I prefer to do something like this all in one place (dops for this example).  The workflow I proposed is something more akin to pflow or tp -- but Houdini is so nice in that you can always do things in steps by caching, and then doing something else off of that cache separately. The workflows for caching and doing things in separate steps is way better in Houdini than tp/pflow.

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Well, for what I wanted to do, stacking POPs worked out really well, but I'm gonna dig in deeper and replicate this setup using the streams tomorrow.

 

And TP is genius, not sure if the streams allow you to shuffle particles around as you can using the TP groups (without breaking the streams) but I'm gonna dig into it until I really get how to work with them. And a side note on TP, sadly you gotta live with 3ds Max to use it - last fall I got tired of that and opted not to upgrade to 2015 and migrated to Houdini. And though I do miss TP and VRay, nowadays I almost start crying when I need to open Max, hehe... ;)

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Yeah man, I used to use TP, but don't miss max at all anymore (maybe just procutter/proboolean when it wasn't crashing). The grouping and stuff you can get very similar results, where if it's in X group, it will have Y operations applied to it. You can put a particle in any group or remove it or have it belong to multiple groups at once -- it was a bit easier to visualize in TP, and the hierarchies and inheritance for groups was nice. I do wish rbds were as quick and easy as TP, but Houdini is catching up fast.  That all being said the fact that you can easily fetch and shuffle data from other parts of the scene / geometry / dopnet is unbeatable. In max you were at the mercy of plugin developers to talk to each other, and hopefully get things to work well with each other. In Houdini there's none of that. 

 

Not sure if you saw it, but there was a screenshot of Vray working in Houdini on google plus (from Vlado) not too long ago... they're playing with the idea at least.  Mantra is a really good renderer too though. Building shaders can be quite awesome once you get used to how attributes work.

 

Edit: I saw the post on sidefx. I forgot about the pop stream nodes. I am having a hard time replicating the same stuff my scene had working. I can't even get color to be applied per group properly in that setup. Things that should be only affecting the incoming stream (from what I understand), or even when I tell it to operate on a specific group it applies color to everything.

Edited by Solitude

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Yeah man, I used to use TP, but don't miss max at all anymore (maybe just procutter/proboolean when it wasn't crashing). The grouping and stuff you can get very similar results, where if it's in X group, it will have Y operations applied to it. You can put a particle in any group or remove it or have it belong to multiple groups at once -- it was a bit easier to visualize in TP, and the hierarchies and inheritance for groups was nice. I do wish rbds were as quick and easy as TP, but Houdini is catching up fast.  That all being said the fact that you can easily fetch and shuffle data from other parts of the scene / geometry / dopnet is unbeatable. In max you were at the mercy of plugin developers to talk to each other, and hopefully get things to work well with each other. In Houdini there's none of that. 

 

Not sure if you saw it, but there was a screenshot of Vray working in Houdini on google plus (from Vlado) not too long ago... they're playing with the idea at least.  Mantra is a really good renderer too though. Building shaders can be quite awesome once you get used to how attributes work.

 

About Max, someone posted a video yesterday of Max 2016 with something looking a lot like ICE implemented, though it was taken down since. That would make Max a lot more like Houdini, seeing ICE is basically VOP's...

 

On the other hand, the main ICE dev's are now employed at SESI (the position based dynamics stuff were from them?) if I understood it right, so porting ICE "as is" to Max will likely mean it's not going to be maintained very well - though that might not be needed either... Well, we'll see.

 

And I did see the screenshot from Vladi, though in Indie at the moment so no external rendering support - sad as I would really have liked to be able to use 3delight with volumes without having to exporting VDB's from Houdini and rendering in 3ds Max - but g'damn 3delight is blazing fast rendering volumes...

 

Edit: I saw the post on sidefx. I forgot about the pop stream nodes. I am having a hard time replicating the same stuff my scene had working. I can't even get color to be applied per group properly in that setup. Things that should be only affecting the incoming stream (from what I understand), or even when I tell it to operate on a specific group it applies color to everything.

 

Mmm, I just replied to a post by Jeff in the Houdini forum, kinda disputing him saying they are groups - because they really aren't as streams break each other when crossed, so to speak. Seems the SESI guy's have a Ghostbuster type issue going on here... ;)

 

But I'm hoping to get a grip of this over the weekend now, figure out what works or not, hopefully the how's and why's of it too. It would be great to be able to feed spawned particles back into the groups that spawned them, that really is part of the genius with how you handle particle groups in TP.

Edited by Farmfield

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You know about genome, right? That's basically vop sops for max. I wouldn't be surprised if Autodesk just bought it/licensed it. I know they're working on that kind of stuff for Maya with bifrost, and ideally they would make it once and use it in both softwares. I don't care though. I'm a convert.

 

Yeah it would be nice if they opened up Indie for 3rd party renderers -- there are arguments for both sides of that I suppose. But progress is progress!

 

I think streams are supposed to be related to the actual network flow, and groups should be more universally accessible anywhere -- buuut I don't know.   It's definitely possible to feed replicated particles into other groups though. Anything you can do in tp or pflow can be made in Houdini. It's just a matter of learning the different workflow. Kind of like going from pflow to tp which act a bit differently from each other.

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You know about genome, right? That's basically vop sops for max.

 

LOL, I just replied exactly that to Michael Stark, discussing ICE on twitter. But with that said, I was never very fond of working in Magma. The whole thing with Houdini, though not 100% true, it's pretty damn unified, in terms of workflow, messing about with attributes. In Max you jump between plugins by different developers and you need a multiple-mindset-approach to many things that I now tackle with one mindset - or lack of one perhaps. :D

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Well, thanks to Ian I have now solved this in a couple of different ways and in the end it was really as easy as keeping it in three groups, one to lead, one to spawn and one to trail. The attached file is the most I could simplify it.

 

But with that said, doing it as simplified as I have produces a pretty "undirectable" setup where any change in values completely changes the whole pattern - compared to stacking POPs on POPs which is amazingly controllable and directable result - and if you really need to do feedback loops, I guess you could always stack POPs on POPs inside a solver node...(?) :D

 

And I think I figured out how to use the streams to now, both how you split them out and how you use the streams node. I will continue to play around with all this until I feel secure I know what the hell I'm doing in POPs,  replicating a couple of my earlier TP setups is probably gonna be the best way for me to reprogram myself from the Thinking Particles- to a Houdini POP's methodology/mentality.

growth.in.one.POP.v1.hiplc

Edited by Farmfield
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