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Thread: Animated GI for interiors and KRay

  1. #1
    eye kan kode gud jrandom's Avatar
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    Animated GI for interiors and KRay

    I've been working on my first animated sequence that involves an interior lit by luminous polygons and no lights and have discovered the horror that is animated GI.

    Been through a lot of threads, read Except's radiosity tutorial... to get anything even close to a clean render for an 8 second shot at 1920x1080 requires just a silly amount of time per frame -- either interpolated MC with tiny, tiny MPR settings, animated cache, etc... or non-interpolated MR which is slower than glaciers if you're not using lights and want non-noisy surfaces.

    So... I've been eyeballing KRay... it's something like $400 which I can technically afford but I had trouble getting clean renders while playing around with the demo version. (I've got no problems with diving into the manuals if that's what it takes to get clean renders, just couldn't figure it out in the few hours I poked around with it).

    For all you KRay users, is it worth the cost if one is going to be doing a lot of interiors with few-to-no lights and lots of luminous polys? Is it really as fast as the sales pitch says?

  2. #2
    Not only it's worth, it's a must. In particular, luminous geometry is handled in a very smart way, you can chose how luminosity should behave - as direct (kinda arealight) or indirect (irradiance only, soft light), and you have plenty of tools to control every aspect of lighting.
    If you plan to work on interiors, exteriors and landscaping (remember Kray has a very fast instancing system for LW) you should really get it.

    Paolo

  3. #3
    eye kan kode gud jrandom's Avatar
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    Quote Originally Posted by Pavlov View Post
    ...In particular, luminous geometry is handled in a very smart way, you can chose how luminosity should behave - as direct (kinda arealight) or indirect (irradiance only, soft light)...
    I just read that part of the KRay manual. I didn't get it. I read it again. I still didn't understand.

    Then... *click*

    ... REALLY??

    *pulls out wallet*

    And I just bought LWCAD, too...
    *sigh*

    (This kinda brings Lightwave closer to the cost of the other programs it competes with. I still feel I made the right purchasing choice because I really like its approach to modeling [despite the drawbacks that lead me to LWCAD in the first place -- I can't even imagine modeling w/out a slew of easily-switchable layers now] and this fantastic yet small user community that manages to be super helpful with very, very few flamewar threads.)

  4. #4
    LW cad is a must as well, good choice !
    Direct/indirect is not something you can understand on paper, you just have to try it and see differences. From that moment, you'll understand you *needed* that in many situations before
    Regarding the fact Lw (and its plugin) comes closer to other competitors, even in terms of cost: let's see it as a good thing. Correct pricing means solid development, cheap is much closer to toyland than you may think.

    bye
    Paolo

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    The Real Homestar. Intuition's Avatar
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    I haven't had much success getting flicker free animation from LW using traditional techniques.

    The method I used, back when I still used LW much, was to do what I call a spinning GI trick which is not too different then the spinning spotlight trick that we used to get soft shadows from spot lights before the days of area lights.

    The process involves using dithered motion blur to blend the individual GI passes together. Dithered motion blur will take each a and b pass if the GI prepass and blend them all together in the final result essentially blurring the GI. This process also blurs the AAliasing through the whole render so you can turn down the AA settings alot and still get super clean renders.

    Finally the test thread we made using this method a few years ago showed people using the 0.5 multiplier which made the GI prepass resolution half of its full value which helps speed things up.

    So instead of using high settings to get a clean render you use overall lower settings.

    http://www.newtek.com/forums/showthr...ered+GI&page=4

    This is a test scene. See if you can reverse engineer what I am doing. This might be a good method to test with native LW renderer.
    -----------------
    KC

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    eye kan kode gud jrandom's Avatar
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    Quote Originally Posted by Pavlov View Post
    LW cad is a must as well, good choice !
    I absolutely love this plug-in.


    Direct/indirect is not something you can understand on paper, you just have to try it and see differences.
    It took me a few minutes, but I'm pretty sure I understand exactly what this does. Because the lumigons are treated as direct light sources, you won't get the noise/grain you'd get in the indirect model where you're hoping the random samples just happen to hit the lumigons by chance.

    Direct == guaranteed light hits == way less noise and artifacting.

    Is this right? Please say it's right because that's fantastic.


    Regarding the fact Lw (and its plugin) comes closer to other competitors, even in terms of cost: let's see it as a good thing. Correct pricing means solid development, cheap is much closer to toyland than you may think.
    As a software developer who can't get paid to write the stuff I want to write (I make a living writing boring telecom data translation programs instead), I fully understand this and will support companies that make good software with my wallet (within reason... I can't exactly justify buying Houdini or anything).
    Last edited by jrandom; 07-22-2010 at 03:03 PM.

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    eye kan kode gud jrandom's Avatar
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    Quote Originally Posted by Intuition View Post
    The method I used, back when I still used LW much, was to do what I call a spinning GI trick...
    If I didn't have so many blurry reflections this might actually work, but as it stands it ballooned out my render times too much. It's a great idea though.

  8. #8
    Hi,

    It took me a few minutes, but I'm pretty sure I understand exactly what this does. Because the lumigons are treated as direct light sources, you won't get the noise/grain you'd get in the indirect model where you're hoping the random samples just happen to hit the lumigons by chance.
    Direct == guaranteed light hits == way less noise and artifacting.
    Is this right? Please say it's right because that's fantastic.
    Yes, but it's not just that.
    Indirect has some advantages over Direct, because it's soft and extremely fast lightening. Usually, large luminous surfaces behave better in indirect mode (lumipolys at windows, skydomes) while small surfaces behave better in direct mode.

    http://www.kraytracing.com/wiki/GUI_...minosity_model

    Results are different and it's not possible to tell which is better, as said you'll find you need (and always needed) both.

    Paolo

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    eye kan kode gud jrandom's Avatar
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    Quote Originally Posted by Pavlov View Post
    Results are different and it's not possible to tell which is better, as said you'll find you need (and always needed) both.
    Yep! As soon as I saw there was an "Automatic" selection w/ threshold that I was sold. (I like being able to bounce around from automatic to manual settings depending on the scene.) Yessir, I am buying this tonight.

    Edit: Correction, have purchased and downloaded and now I have to wait until I get home from work to start using it and oh boy do I hate waiting GRR RAR...

    With all these new programs I'm getting it's difficult to restrain my inner child from yelling TOYS TOYS TOYS TOYS TOYS!!! while bouncing around the room like a madman.
    Last edited by jrandom; 07-22-2010 at 03:46 PM.

  10. #10
    The Real Homestar. Intuition's Avatar
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    Quote Originally Posted by jrandom View Post
    If I didn't have so many blurry reflections this might actually work, but as it stands it ballooned out my render times too much. It's a great idea though.
    Oh yeah, blurry reflections with GI equals slow with that cheat method.

    Might I suggest Vray..

    Seriously though, Kray is awesome but I can't say I've seen alot of animation with it to say it effectively reduces flicker without going into long rendertimes. This is only due to the fact that I haven't used it in the last year much.
    -----------------
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  11. #11
    eye kan kode gud jrandom's Avatar
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    Quote Originally Posted by Intuition View Post
    Might I suggest Vray..
    Hah! Oh lordy, that is one expensive renderer. They also don't have a Lightwave version and I'm not yet at the stage where I need something that fancy yet.

    Seriously though, Kray is awesome but I can't say I've seen alot of animation with it to say it effectively reduces flicker without going into long rendertimes. This is only due to the fact that I haven't used it in the last year much.
    It can't be any worse than the native LW renderer for the indoor-scene case and after looking over the feature set I can definitely say I need what it offers, especially since I like both blurry reflections and luminous polygons.

    Lightwave still does an excellent job at outdoor/open scenes so I will most likely wind up using both renderers on a regular basis.

  12. #12
    eye kan kode gud jrandom's Avatar
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    Oh hey, this brings up another question. When I was playing around with the KRay demo, I noticed that once I started using it I couldn't figure out how to switch back to the native LW renderer for that scene (making it more difficult to do comparisons).

    Is there an easy way to switch back and forth?

  13. #13
    Super Member geo_n's Avatar
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    I love kray. I've been bugging the developer for more features that will make it animation and composite friendly (the alpha and matt channels need to be supported).
    With that said, it will be superfast for walkthrough type animation. I have not successfully rendered animated objects(deforming not rigid objects) without zero flicker though. I'm also a vray user and vray can flicker as well and the only way to get flicker free animation for me is to use irridiance cache and bruteforce passes when it comes to enclosed spaces. But it is very fast compared to lw montecarlo or kray uncached gi. Maybe the next kray engine will have faster uncached gi or something like bruteforce which is not exactly full blown montecarlo.

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    Super Member geo_n's Avatar
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    Quote Originally Posted by jrandom View Post
    Oh hey, this brings up another question. When I was playing around with the KRay demo, I noticed that once I started using it I couldn't figure out how to switch back to the native LW renderer for that scene (making it more difficult to do comparisons).

    Is there an easy way to switch back and forth?
    render globals panel>render, below is the renderer options to switch to lw or kray.

  15. #15
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    Quote Originally Posted by geo_n View Post
    render globals panel>render, below is the renderer options to switch to lw or kray.
    Oh hey. Right there in front of me.

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