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Thread: PFX: scene autopsy-- what's going on here (attached)

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    Axes grinder- Dongle #99
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    Question PFX: scene autopsy-- what's going on here (attached)

    Just trying to follow a tutorial on YouTube: (see attached) why is it that the collision with the Collision Object doesn't cause the emitter to cough out particles until it's almost reached the end of the object? That is, why doesn't emitting being as soon as contact begins?

    Thanks.

    EmissionVertices.zip

    ++++
    MORE: managed to get it to do zero just by playing around (scaling emitter object). Oh, what fun.
    ++++
    MORE2: So, if I bring the collision object in from the minus X side, it works as expected, but if I bring it in from the plus X side, it does not.

    -- Of course. :eyeroll:
    Last edited by jeric_synergy; 04-13-2016 at 08:14 PM.
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    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    Just trying to follow a tutorial on YouTube: (see attached) why is it that the collision with the Collision Object doesn't cause the emitter to cough out particles until it's almost reached the end of the object? That is, why doesn't emitting being as soon as contact begins?

    Thanks.

    EmissionVertices.zip

    ++++
    MORE: managed to get it to do zero just by playing around (scaling emitter object). Oh, what fun.
    if you use nozzle surface it would work..but thatīs not what you want, but the thing is it has trouble reading the vertices location it seems, so go to the object properties of the tropical emitter/fx and then particle tab, uncheck fixed random and now it should work with vertices.

    And to counterpart the calling of evil spirits

  3. #3
    Axes grinder- Dongle #99
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    Quote Originally Posted by prometheus View Post
    if you use nozzle surface it would work..but thatīs not what you want, but the thing is it has trouble reading the vertices location it seems, so go to the object properties of the tropical emitter/fx and then particle tab, uncheck fixed random and now it should work with vertices.
    Well, that's just begging the question, isn't it: WHY would it have issues with detecting the vertices on this dead-simple object?

    Also: why does it work when the collision object approaches from minus X and not plus X??

    Seriously, working with this made me dl Blender. :P
    (I'm not kidding.)
    They only call it 'class warfare' when we fight back.
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  4. #4
    Axes grinder- Dongle #99
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    I also have seen issues with the BIRTHRATE parameter repeatedly being set to zero. This happens regularly, though at unpredictable intervals.
    They only call it 'class warfare' when we fight back.
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    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    Well, that's just begging the question, isn't it: WHY would it have issues with detecting the vertices on this dead-simple object?

    Also: why does it work when the collision object approaches from minus X and not plus X??

    Seriously, working with this made me dl Blender. :P
    (I'm not kidding.)
    Not sure exactly, but I suspect the fixed random option overides some default parameter on how the particles are positioned to get a different distribution that is not so random, and by doing so it seems it brute force change the original position...thus the particles are not recognized properly by this collision even, problem solved anyway right?

    Yeah..blender, you will go grr.because of other stuff in there, it has different ways of working with particles...cool to be able to use paint weight maps though and use that as birth emitter..but other things will be more awkward and harder than to use lightwave relativly easy to set up particles.

    You got to get used to the blender UI ...so good luck with that.

    Michael

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    Axes grinder- Dongle #99
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    Quote Originally Posted by prometheus View Post
    Not sure exactly, but I suspect the fixed random option overides some default parameter on how the particles are positioned to get a different distribution that is not so random, and by doing so it seems it brute force change the original position...thus the particles are not recognized properly by this collision even, problem solved anyway right?
    I have no idea what you are saying here.
    They only call it 'class warfare' when we fight back.
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    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    I have no idea what you are saying here.
    no need to..the problem is fixed anyway, just make sure to uncheck fixed random, for what it does..hard to describe...this is what is documented in the 2015 help files..

    "Particle resistance adds an air resistance effect. Particles will move slower as you increase this value.
    Life time (frame) sets the life of the particles in frames. Once a particle is born, it lasts only this long.
    If you activate Fixed Random, random calculations are constant, so they yield more predictable
    results."


    Maybe that will not make you wiser, only more confused

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    Axes grinder- Dongle #99
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    Prom, I often find your "stream of consciousness" style of posting difficult to understand-- you may want to give more context to your writing, since sometimes to me it seems extremely disjointed. FWIW & YMMV.

    For instance, I'm not sure why you think this problem is resolved.
    They only call it 'class warfare' when we fight back.
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    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    Prom, I often find your "stream of consciousness" style of posting difficult to understand-- you may want to give more context to your writing, since sometimes to me it seems extremely disjointed. FWIW & YMMV.

    For instance, I'm not sure why you think this problem is resolved.
    Yes..sorry to say..I have noticed that is the case quite often with you and me, not sure if itīs my way of thinking ..or if it is how it translates in bad english translation from me..without consistency, good to know how you perceive it...and I will keep it in mind.

    Or Maybe our way of reasoning is on quite a different bandwith so to speak..if you understand some folks understand eachother better or less better..even if they are from the same country etc.

    You say for instance this..and point to why I would think the problem is solved? I would say that has nothing to do with my thinking..I would say you should tell me if it worked or not? at my end it works..problem solved, if you on the other hand did not get it solved by unchecking fixed random?...then I haved no clue unless you verify it back, so..did it work or not?

    The question on why it is working or not working ?..that is a different matter..maybe not for you, sure..one may want to know Exactly why it works like it do..fully understandable..and I see that is something you seem to want...But sometimes I surrender to the fact that tools are not properly described or completly lacking and I can not get the full understanding of it..and I am in fact just guessing.... and that is why you feel my thoughts disjointed?

    So now I am confused wether or not I did help you in this matter?
    If you had serious issues understanding this..then I think our communication is in severe trouble.

  10. #10
    it's a manhole cover ↓ JoePoe's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    Just trying to follow a tutorial on YouTube:
    What tutorial? Link? Are you getting a different result then they do?

    It appears that particle generation is taking point order into consideration when birth rate is set to vertices.
    Once vertex #1 is contacted, all others become "alive" in order. If you're coming at the object from the direction opposite to point order, nothing happens until point #1 is hit. Because the collision object at that moment is already in contact with #s 2,3,4,5,6, etc, those fire simultaneously along with #1.

    Why? Dunno? never noticed that before. I could be way off..... just my impression.

    Edit: Here's another example. Collision ball hitting the corner of a flat plane. Corner point is vertex #1.

    Click image for larger version. 

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    Points 1-6 are hit (for all intents and purposes) at the same time. #7 slightly later.
    None of the other points (which clearly have been contacted by the collision object) have fired... even though they were hit first by the leading curve of the sphere. The next point to fire is #8 which was missed.
    Last edited by JoePoe; 04-15-2016 at 10:49 AM.
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    It's on my other machine: recently on FB, results in a kind of "tropical flower" look. Quite nice, although the audio/text free tutorial is a chore to view.

    I'm thinking you're onto something, JP: that certainly looks right. I've submitted the scene to LWG bug fixers. I'll add your speculation. The tute uses SURFACE, so the poster would not have run into this. Still, needs to be quashed.

    There's some really intriguing stuff on YT if you search "lightwave particles".

    I have the impression that emission direction is somehow affected by the trigger object: is that likely? While it is technically a "collision" object, I'm using it mainly as a trigger: is collliding per se a default?
    They only call it 'class warfare' when we fight back.
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    RETROGRADER prometheus's Avatar
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    I donīt see why a collision Event would affect the direction, it has nothing to do with it, just birthrate...if it in your scene does have that effect..then you might have something else going on, otherwise truly a bug..but based on what I can see on the provided scenefile, that shouldnīt be the case.

    You do however have explosion force in there..that is probably what is directing the particles, turn that of and you should have nothing of directional particle motion to speak of.
    And you also got a setting of -4.7 in x velocity for the particles...which of course pushes the particles.
    Unless you talk about other scene attempts?

    Turning off explosion and velocity motion, and you will see how the particles is distributed on the cylinder at the end, check and uncheck fixed random and you see the difference..finally turn on fixed random again...and change birth rate to different values..and you see some differences...I wonīt go in to much more in to detail on that, since I am not completly sure whatīs going on...regarding birthrate, fixed random and how it calculates particles according to the help files ..

    "Particle resistance adds an air resistance effect. Particles will move slower as you increase this value.
    Life time (frame) sets the life of the particles in frames. Once a particle is born, it lasts only this long.
    If you activate Fixed Random, random calculations are constant, so they yield more predictable
    results."


    Hope the bug crushers can help you out better than I.. my expertis is limited here, I only gave you sojme feedback on my findings here.

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    RETROGRADER prometheus's Avatar
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    Of course...rotate the cylinder 180 degrees in the heading direction... and you wonīt even have to mess with fixed random, it should start emitt when the collision event object arrives..since we mentioned particles following point order, those points that made up the cylinder in your case was at the end, so rotating the cylinder perhaps is one solution? simple as that?..ehh point order was of course also mentioned already by joepoe.

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    Axes grinder- Dongle #99
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    A lot of this isn't about a specific object, it's about generalized workflow. This is a test object, why would it behave so oddly? An actual object would have specific orientation that couldn't blithely be flipped about.

    I don't want to have to continually second guess my tools: they should work as expected.
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

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    RETROGRADER prometheus's Avatar
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    Quote Originally Posted by jeric_synergy View Post
    A lot of this isn't about a specific object, it's about generalized workflow. This is a test object, why would it behave so oddly? An actual object would have specific orientation that couldn't blithely be flipped about.

    I don't want to have to continually second guess my tools: they should work as expected.
    I Understand that, though I donīt think itīs a matter of a bug in terms that something got wrong in the latest versions..maybe call it lack of proper feature, this is how particles works..following point order I guess, so maybe by entering nodes and change point order, or use some model plugin to re-arrange point order, until the lw team develops it so it doesn matter..if possible that is.

    I understand why you mentionen general workflow...Now, but you didnīt for your very first post it was a matter of this case and not a general workflow with other situations..at least that didnīt came through in the first posts.
    It isnīt like you said,...this have to work not only on this object, but on other objects that canīt be blithely flipped about.

    Initially It was a question on what is going on Here...not a question described as..(by the way thereīs all other possible object or scene variations this must work on), you at least got answers to why it works on one minus x side...which isnīt specificly related to minus x or plus x sides, rather how the cylinder was created with itīs point order.

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