does luxrender do caustics?

MistaraMistara Posts: 38,675
edited December 1969 in The Commons

i'm staring at the icon, wondering if today is the day to click it and start learning it?

Comments

  • JimmyC_2009JimmyC_2009 Posts: 8,891
    edited December 1969
  • MistaraMistara Posts: 38,675
    edited October 2012

    kewl. Thanks! i'm hoping for the kind of caustics that will pick up colors from like a stained glass window.

    i'm serving too many software overlords. :lol: before midnight today, i'm gonna try to pick 3, and stick with them, until i know em proficiently.

    Post edited by Mistara on
  • cwichuracwichura Posts: 1,042
    edited December 1969

    Yes, Lux does caustics without any special tricks. For the most part, just set a material to glass2 with a clear volume defined on its interior. (What Reality calls 'hyper-realistic' glass in it's "friendly" naming, if you're using Reality to do the export.) Reality's Water pseduo-material is also ultimately glass2 with a clear volume 'under the hood'. Here's an example of the water creating caustics reflections on the legs of the swimmer: Slipping In (NSFW)

  • Joe CotterJoe Cotter Posts: 3,259
    edited December 1969

    Question is, do you want to learn Lux or go with Octane. Daz Internal with UberEnvironment combined with Octane looks like a better combination at this point.

  • MattymanxMattymanx Posts: 6,904
    edited December 1969

    Gedd said:
    Question is, do you want to learn Lux or go with Octane. Daz Internal with UberEnvironment combined with Octane looks like a better combination at this point.

    Octane will not use UE any more then LuxRender will.

  • cwichuracwichura Posts: 1,042
    edited December 1969

    Gedd said:
    Question is, do you want to learn Lux or go with Octane. Daz Internal with UberEnvironment combined with Octane looks like a better combination at this point.

    Octane's main pro is speed. But it's currently only a path renderer, which means it will have trouble with some things, such as caustics like the OP asked about, and may never fully converge despite how long it is left to run. It also requires an nVidia GPU, as it only works with CUDA GPUs. Octane also requires one to think much more in terms of procedural textures, to get around the limitation of having all geometry and textures fit in GPU memory (which is typically much smaller than main system memory).

    LuxRender supports more rendering algos like bidir and SPPM, so can more easily render 'difficult' scenes, albiet more slowly than Octane. Lux supports OpenCL for GPU-assisted rendering, so will work with any GPU platform. But its GPU rendering isn't really ready for prime-time, yet (Hybrid Path is OKish, Hybrid Bidir still needs a lot of work). Because it does hybrid rendering, only the geometry has to fit in GPU memory. Textures remain in CPU memory, so it can use the GPU for much more complicated scenes. However, hybrid rendering isn't as fast as GPU-only rendering like Octane does.

    Personally, I use Lux. But I use Lux's built-in network rendering support to help reduce my render times. And even with multiple machines cranking on a scene, it can still take a couple days for some renders to bake.

  • mjc1016mjc1016 Posts: 15,001
    edited December 1969

    cwichura said:
    Gedd said:
    Question is, do you want to learn Lux or go with Octane. Daz Internal with UberEnvironment combined with Octane looks like a better combination at this point.

    Octane's main pro is speed. But it's currently only a path renderer, which means it will have trouble with some things, such as caustics like the OP asked about, and may never fully converge despite how long it is left to run. It also requires an nVidia GPU, as it only works with CUDA GPUs. Octane also requires one to think much more in terms of procedural textures, to get around the limitation of having all geometry and textures fit in GPU memory (which is typically much smaller than main system memory).

    LuxRender supports more rendering algos like bidir and SPPM, so can more easily render 'difficult' scenes, albiet more slowly than Octane. Lux supports OpenCL for GPU-assisted rendering, so will work with any GPU platform. But its GPU rendering isn't really ready for prime-time, yet (Hybrid Path is OKish, Hybrid Bidir still needs a lot of work). Because it does hybrid rendering, only the geometry has to fit in GPU memory. Textures remain in CPU memory, so it can use the GPU for much more complicated scenes. However, hybrid rendering isn't as fast as GPU-only rendering like Octane does.

    Personally, I use Lux. But I use Lux's built-in network rendering support to help reduce my render times. And even with multiple machines cranking on a scene, it can still take a couple days for some renders to bake.

    Lux's SPPM implementation is a great trade off between speed and 'good looks'. I use it all the time, and while not as fast as a GPU render, get acceptable results in under an hour in most things and if I borrow the 'media center' and my son's computer and render over the network even faster. (heck, I can even throw in the wife's and daughter's laptops if I wanted...). One thing that really matters, with both Lux and Octane...final size of the render.

    And it does caustics, quite nicely.

    Lux network rendering is a breeze to use...

  • MattymanxMattymanx Posts: 6,904
    edited December 1969

    mjc1016 said:
    One thing that really matters, with both Lux and Octane...final size of the render.


    Octane is limited to the GPU memory while Lux is limited to the system memory. Lux can use all the Virtual memory that you throw at it too so it is far more capable of handling larger and more complicated scenes then Octane can.

  • cwichuracwichura Posts: 1,042
    edited December 1969

    Mattymanx said:
    Lux can use all the Virtual memory that you throw at it too

    I have to disagree on this one statement. Lux pretty much constantly touches all of its memory space during rendering ALL the time. Thus, there are no areas of the Lux process that can 'settle' on disc when swapped out by the VM manager. When I do renders that are too large for physical memory, it ends up causing the OS to page swap so hard that it kills the machine and the only way to get it back is to hard reboot. At least that's been my experience.

    But yes, Lux can still render more complex scenes, since it's much easier to add CPU memory than GPU memory.

  • Joe CotterJoe Cotter Posts: 3,259
    edited October 2012

    Mattymanx said:
    Gedd said:
    Question is, do you want to learn Lux or go with Octane. Daz Internal with UberEnvironment combined with Octane looks like a better combination at this point.

    Octane will not use UE any more then LuxRender will.

    You obviously misunderstood what I was saying...

    Daz internal with UberEnvironment fits render situations that Octane doesn't... between the two... it makes a pretty nice package.

    Post edited by Joe Cotter on
  • MistaraMistara Posts: 38,675
    edited December 1969
  • greymouser69greymouser69 Posts: 501
    edited December 1969

    Lets face it, comparing lux with some other renderers is not really possible, they have totally different design considerations. All are good and very capable in their own right but they each do things differently. Lux itself is based upon the real world physics of how light operates and interacts with various materials while renderers like studio (3DLite), Octane, and even Bryce take certain shortcuts in order to achieve their results. Each one is excellent at what they do and are highly useful but trying to compare them is pretty much pointless.

    If you are a photographer you will probably be more comfortable with lux than others since it accurately emulates things like shutter speed, film iso, and f-stops naturally rather than the shortcuts other renderers take. In fact, it can even take into account different types of film stock and how they respond to light naturally. If you are after TRUE "photo-realism" then lux is the winner hands down. But be warned, this type of render will take a serious amount of time due to the calculations necessary to support it. Another thing is to remember that lux is a non-biased renderer mostly which means that it will never "finish" a render until you tell it to; it can run for months or even years if you are willing to let it go. How "finished" it is is generally measured in samples/pixel (s/p in the display) and some scenes can be done relatively soon like 500 s/p or so while others may take longer like around 2000-2500 s/p or even more. There is generally a "break-even" point where further processing will not be likely to improve things much more than they currently are.

    In the end, reality/lux is just another tool for your toolbox and should be used as such depending on your needs and/or desires.

  • Joe CotterJoe Cotter Posts: 3,259
    edited October 2012

    .

    Post edited by Joe Cotter on
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