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Instancing optimization

ramialmasryramialmasry Posts: 0
in Technical Help (nuts n bolts)

can someone explain to me whats the differnce between Memory, speed and auto ? 

i looked around and couldnt find anything useful

i tried to render same scene with both options, and the attached render with more light is the one with speed option

that light is ghost light (i dont know if that matter)

thank you

 

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Comments

  • Richard HaseltineRichard Haseltine Posts: 100,730

    It has to do with how "instances" - clones of a single item - are handled. One way uses more memory but is faster, the other is slower but ess demanding on memory.

  • chris-2599934chris-2599934 Posts: 1,804
    Richard Haseltine said:

    One way uses more memory but is faster

    Faster, in theory maybe, but whenever I've accidentally left it set to "speed" it causes my machine to grind to a halt, crash, and need to be rebooted (twice, sometimes) before I can do it again - much faster - with the memory setting.

  • ramialmasryramialmasry Posts: 0

    as far as i understand instances it affect objects and lower memory usage.

    but why is affecting lighting ? there is a ghost light from this product (iray ghost light kit 3) on her back, is that considered clone or instance of something ?

    i read somewhere to never use auto, is this true ?

    thank you for your answer

  • ramialmasryramialmasry Posts: 0
    chris-2599934 said:
    Richard Haseltine said:

    One way uses more memory but is faster

    Faster, in theory maybe, but whenever I've accidentally left it set to "speed" it causes my machine to grind to a halt, crash, and need to be rebooted (twice, sometimes) before I can do it again - much faster - with the memory setting.

    i did a test for the same scene, 30 min each 

    the renders  are in my previous post

    memory option:  24% convergance rate

    speed option : 34% convergence rate

    so its clearely affect the speed but i am wondering why its affecting the lighting =/

  • marblemarble Posts: 7,500
    edited March 2021

    I have not come across this before - probably because I have not used products with lots of instances. However I recently bought the product "Harpwood Trail", loaded it and tried to render. I was amazed to find that it dropped to CPU on my brand new monster RTX 3090 which has 24GB VRAM. I also have 64GB system RAM. 

    I went back to the product page for the Harpwood Trail and noticed that there is a note to switch Instancing Optimization to "Memory" rather than "Speed" although, looking through a few forum comments on this, it seems the recommendation is to cater for low end GPUs with not much VRAM. Anyhow, I tried switching to "Memory" and, sure enough, it renders on my 3090 without a problem in "Memory" mode. Still only in CPU mode if I switch back to "Speed". 

    According to the IRay report window and GPU-Z, the scene uses 17GB VRAM (well below my 3090 limit of 24GB) in "Speed" mode and less than 5GB in "Memory"mode. I don't understand why my 3090 ca't handle the scene in "Speed" mode, not that it is really a problem because the scene renders quite quickly in "Memory" mode anyway. I am just confused as to why it drops to CPU when I have plenty of VRAM.

    harpwood.jpg
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    Post edited by marble on
  • margravemargrave Posts: 1,822
    edited March 2021

    marble said:

    ​According to the IRay report window and GPU-Z, the scene uses 17GB VRAM (well below my 3090 limit of 24GB) in "Speed" mode and less than 5GB in "Memory"mode. I don't understand why my 3090 ca't handle the scene in "Speed" mode, not that it is really a problem because the scene renders quite quickly in "Memory" mode anyway. I am just confused as to why it drops to CPU when I have plenty of VRAM.

    I had a similar issue when I tried to render a character at 4 SubD. Theoretically, if I quadrupled the geometry memory consumption from 3 SubD, it should've fit into my 8GB of RAM. But for whatever reason it bombed out. I guess there's just some hidden overhead we're not privy to.

     

    ramialmasry said:

    can someone explain to me whats the differnce between Memory, speed and auto ? 

    i looked around and couldnt find anything useful

    i tried to render same scene with both options, and the attached render with more light is the one with speed option

    that light is ghost light (i dont know if that matter)

    thank you

    I know this is a necrothread, but for future reference:

    Memory: Conserves memory by using instances.

    Speed: Disables instances and gives every object its own copy of the geometry, which I guess is faster somehow.

    Auto: In theory, tries to smartly recognize which one of the above to use. In practice, gives your characters hideous orange spray-tan skin and black eyes if they're too far from 0,0,0, so learn to avoid it.

    Post edited by margrave on
  • marblemarble Posts: 7,500

    margrave said:

    marble said:

    ​According to the IRay report window and GPU-Z, the scene uses 17GB VRAM (well below my 3090 limit of 24GB) in "Speed" mode and less than 5GB in "Memory"mode. I don't understand why my 3090 ca't handle the scene in "Speed" mode, not that it is really a problem because the scene renders quite quickly in "Memory" mode anyway. I am just confused as to why it drops to CPU when I have plenty of VRAM.

    I had a similar issue when I tried to render a character at 4 SubD. Theoretically, if I quadrupled the geometry memory consumption from 3 SubD, it should've fit into my 8GB of RAM. But for whatever reason it bombed out. I guess there's just some hidden overhead we're not privy to.

     

    ramialmasry said:

    can someone explain to me whats the differnce between Memory, speed and auto ? 

    i looked around and couldnt find anything useful

    i tried to render same scene with both options, and the attached render with more light is the one with speed option

    that light is ghost light (i dont know if that matter)

    thank you

    I know this is a necrothread, but for future reference:

    Memory: Conserves memory by using instances.

    Speed: Disables instances and gives every object its own copy of the geometry, which I guess is faster somehow.

    Auto: In theory, tries to smartly recognize which one of the above to use. In practice, gives your characters hideous orange spray-tan skin and black eyes if they're too far from 0,0,0, so learn to avoid it.

    Thanks for that explanation - the definitions now make sense.

    As I said, I don't have many scenes with instances but quite a few of these landscape scenes have been in the March sale and I have bought some. Now I know how to use them. Still disappointed that DAZ Studio still manages to crash my monster GPU though. 

  • PerttiAPerttiA Posts: 10,024

    marble said:

    margrave said:

    marble said:

    ​According to the IRay report window and GPU-Z, the scene uses 17GB VRAM (well below my 3090 limit of 24GB) in "Speed" mode and less than 5GB in "Memory"mode. I don't understand why my 3090 ca't handle the scene in "Speed" mode, not that it is really a problem because the scene renders quite quickly in "Memory" mode anyway. I am just confused as to why it drops to CPU when I have plenty of VRAM.

    I had a similar issue when I tried to render a character at 4 SubD. Theoretically, if I quadrupled the geometry memory consumption from 3 SubD, it should've fit into my 8GB of RAM. But for whatever reason it bombed out. I guess there's just some hidden overhead we're not privy to.

     

    ramialmasry said:

    can someone explain to me whats the differnce between Memory, speed and auto ? 

    i looked around and couldnt find anything useful

    i tried to render same scene with both options, and the attached render with more light is the one with speed option

    that light is ghost light (i dont know if that matter)

    thank you

    I know this is a necrothread, but for future reference:

    Memory: Conserves memory by using instances.

    Speed: Disables instances and gives every object its own copy of the geometry, which I guess is faster somehow.

    Auto: In theory, tries to smartly recognize which one of the above to use. In practice, gives your characters hideous orange spray-tan skin and black eyes if they're too far from 0,0,0, so learn to avoid it.

    Thanks for that explanation - the definitions now make sense.

    As I said, I don't have many scenes with instances but quite a few of these landscape scenes have been in the March sale and I have bought some. Now I know how to use them. Still disappointed that DAZ Studio still manages to crash my monster GPU though. 

    No surprice with forests, every one of those leaves has geometry and materials. One leaf doesn't use much resources, but if you count all of them and use that number to multiply the resource usage of one leaf... It does come up with respectable numbers, not even talking about how the lighting is calculated.

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