There is a lot of color noise in the water droplets. Do you think that's coming from the domelight?
Or do you perhaps have dispersion enabled? (dispersion is known for noise, given it needs to split a ray up into separate wavelengths)
Have you tried a denoiser to reduce the noise?
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Solaris and Karma » Karma XPU noise
- brians
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Technical Discussion » Karma XPU - dual 4090 RTX setup - performance issues
- brians
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Polybud
Referring to the above quote, could anyone help me out with the info, as where and under what circumstances Karma XPU is using higher than fp32 precision?
I got lost reading GnomeToys reply sorry, but I’ll try to cover XPUs gpu/multi-device architecture briefly, which will hopefully clarify any understanding.
XPU treats each device (including the CPU device) as a separate entity. There is no memory sharing between devices. They do not know about each other or communicate. They each have a separate copy of the scene data.
Xpu instructs each of them to render separate passes of the image (some will do this faster than others), which it receives and blends into the final image in whatever order they arrive.
This is a failsafe architecture because it doesn’t matter what combination of devices someone has, or if (eg) one of them fails or whatever, we still end up with the same final result.
For this to work, each type of device needs to produce the EXACT same result (including the cpu device). So to this end we only use fp32 calculations across all devices.
Edited by brians - 2024年2月24日 02:19:45
Technical Discussion » A problem with ocean rendering in karma
- brians
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jsmack
The original problem texture is one built into Houdini, a color lookup ramp of some kind. Perhaps the Houdini tools do not abide the round down rule when creating mips for exr?
Oh appologies, we fixed this bug in 20.0.584
What version of Houdini is the original poster on?
Edited by brians - 2024年2月20日 20:17:36
Technical Discussion » A problem with ocean rendering in karma
- brians
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hfsxddut
What is miplevel and "round-down" mode?
As Gordon says, its to do with the resolution of the miplevels in the texture.
So to create the miplevels, we take the main image and resize it by half, and store it as miplevel 1. Then for level 2 we halve level 1. And so on...
For images that have awkward image sizes, for example 230x180, then the halving will produce 115.5x90. But because we can't have 1/2 a pixel, we need to round the 115.5 either up to 116 or down to 115. GPUs can only handle "round-down" mode, so for XPU if we ever detect an image with "round-up" mode, then we stop loading the mipchain at the problem level.
GnomeToys
usually it was more important back before anisotropic filtering was standard on GPUs so textures didn't flicker in the distance
Its still standard, and we will get flickering if we don't have the correct mips/filtering.
hfsxddut
How can I solve the problem?
To fix this you can...
- regenerate the EXR using "round-down" mode (I'm not familiar with your tool chain, so can't say how to do this sorry)
- regenerate the EXR with no mips at all (XPU will then automatically create them, and cache the result on disk)
- resize the EXR to a power-of-two size.
Solaris and Karma » Karma XPU crash A6000
- brians
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chilby
Is this a permanent solution, or just a debugging tool as you said @brianns?
You should be fine leaving this enabled (for any 550+ driver) until you hear otherwise.
We'll reply on this thread once we hear back from NVidia in the coming weeks.
Solaris and Karma » Setting up Whitewater shader in MaterialX?
- brians
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I can also say that we're looking into supporting level-sets for the next major release of Houdini. These are implicit surfaces defined by a volume and provide a possible whitewater solution.
Solaris and Karma » Setting up Whitewater shader in MaterialX?
- brians
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Hi all
Sorry for the lack of replies on this thread. I'm not a whitewater expert, so I'll ask a few at SideFX who are and get back to you.
regarding disks, XPU cannot render points as disks but we plan to add this capability soon.
Hopefully we can get view-facing as well as oriented. It is conceptually possible to orient the disk to be facing the incoming ray, but I'm not sure what happens with things like reflection or shadow rays. Some hackery might be needed in that regard.
Sorry for the lack of replies on this thread. I'm not a whitewater expert, so I'll ask a few at SideFX who are and get back to you.
regarding disks, XPU cannot render points as disks but we plan to add this capability soon.
Hopefully we can get view-facing as well as oriented. It is conceptually possible to orient the disk to be facing the incoming ray, but I'm not sure what happens with things like reflection or shadow rays. Some hackery might be needed in that regard.
Technical Discussion » Karma sequence render issue, exit code -1073741819
- brians
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sniegockiszymon
I've 551.52 and with this enviro var set to 1 or 0 issue still occurs. (I dont have hairs in scene). With 546.33 and set to 0 seems to work fine, but other cuda errors (like bad memory adress?) often occurs
Ok, this sounds like another driver issue :/
Can you put together a repro scene (+ instructions) and submit as a bug?
thanks a lot
Solaris and Karma » Karma XPU crash A6000
- brians
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jarjarshaq
I can give this a try tomorrow and report back
thanks
jarjarshaq
Out of curiosity, what does this environment variable do? I don't see it listed in the docs.
It makes XPU send code/instructions to Optix using the newer OptixIR format, rather than the traditional PTX format.
Its a developer switch that we use for debugging and would normally make no difference to a user. But in this case the PTX interpreter is crashing so it offers a temporary workaround. We don't document these internal/developer/debug switches because they change often, are somewhat meaningless to a user, and can sometimes cause instability if used incorrectly.
Solaris and Karma » Karma XPU just stops rendering after some frames?
- brians
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What happens if you render using Karma CPU instead?
also, what happens if you render with GPU disabled with XPU (ie envvar KARMA_XPU_DISABLE_OPTIX_DEVICE=1 )
What driver are you on?
cheers
also, what happens if you render with GPU disabled with XPU (ie envvar KARMA_XPU_DISABLE_OPTIX_DEVICE=1 )
What driver are you on?
cheers
Solaris and Karma » Karma XPU crash A6000
- brians
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What happens if you try this environment variable?
KARMA_XPU_OPTIX_ENABLE_OPTIXIR=1
If that still does not work, what happens if you roll back to some 545+ driver? (eg 546.33?)
Please keep in mind, if you use this driver, then you'll need to set the above environment variable to 0
KARMA_XPU_OPTIX_ENABLE_OPTIXIR=1
If that still does not work, what happens if you roll back to some 545+ driver? (eg 546.33?)
Please keep in mind, if you use this driver, then you'll need to set the above environment variable to 0
Technical Discussion » Karma sequence render issue, exit code -1073741819
- brians
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We've found the 550+ NVidia drivers have an issue.
To fix it you can set this environment variable
KARMA_XPU_OPTIX_ENABLE_OPTIXIR=1
but if you drop back to a 545 driver, then it needs to be set back to 0
Please let us know if that solves your issues with the 550+ drivers.
We're waiting on a response from NVidia to confirm the issue on their end, and any kind of estimate on when it might be fixed.
To fix it you can set this environment variable
KARMA_XPU_OPTIX_ENABLE_OPTIXIR=1
but if you drop back to a 545 driver, then it needs to be set back to 0
Please let us know if that solves your issues with the 550+ drivers.
We're waiting on a response from NVidia to confirm the issue on their end, and any kind of estimate on when it might be fixed.
Solaris and Karma » XPU does not treat emitting volume as lightsource
- brians
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Technical Discussion » What happens if XPU scene exceeds VRAM?
- brians
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GnomeToys
CUDA's default behavior in newer drivers is to allow the drivers to manage spilling data that hasn't been used in a long time into system memory at the cost of huge slowdowns if all data is in frequent use, but they'll never OOM unless you're low on system memory too. This option can be turned off in the control panel
I've found it performant, but I have a laptop with integrated GPU.
We're waiting on some more information from NVidia regarding this feature (eg it seems to not work with multiple GPUs). Once we have that we'll make a more formal post outlining its behavior and what that means for XPU users.
Edited by brians - 2024年2月1日 03:59:31
Technical Discussion » Karma sequence render issue, exit code -1073741819
- brians
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Qhuman
same here 551.23 got the same error while karma XPU rendering.
p.s. Rolling back to 546.33 fixed the problem.
What happens if you roll back to 546.33?
Technical Discussion » Solaris Fails to Render Karma Pyro Material
- brians
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newmethos
I am using the Karma Pyro Material to render the simulation using the XPU engine.
Do you get the same issue with Karma CPU vs Karma XPU?
Technical Discussion » Karma XPU CUDA fails at longer frame ranges like 4000 frames
- brians
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This is strange, I'm guessing something to do with the OpenCL at the earlier stages is putting the driver in a bad state, which later affects XPU.
Can you please post the exact CUDA error string you get?
And better yet, post a screenshot of it (this forum often strips out the error message for some reason, something to do with the square brackets)
Also, try forcing OpenCL to use the CPU with the following envvar.
HOUDINI_OCL_DEVICETYPE=CPU
Thanks
Can you please post the exact CUDA error string you get?
And better yet, post a screenshot of it (this forum often strips out the error message for some reason, something to do with the square brackets)
Also, try forcing OpenCL to use the CPU with the following envvar.
HOUDINI_OCL_DEVICETYPE=CPU
Thanks
Technical Discussion » Karma XPU CUDA fails at longer frame ranges like 4000 frames
- brians
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So just to repeat, you're saying that CUDA/Optix work in the viewport, and with low frame-ranges (eg 1000)
But you get this "Failed to initialize CUDA" error if you render over 4000 frames?
Are you on linux or windows?
Are you able to see what kind of memory usage you're getting on the GPU during this caching process?
But you get this "Failed to initialize CUDA" error if you render over 4000 frames?
Are you on linux or windows?
Are you able to see what kind of memory usage you're getting on the GPU during this caching process?
Solaris and Karma » reinitialize optix device after device fail (karma xpu)
- brians
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Solaris and Karma » reinitialize optix device after device fail (karma xpu)
- brians
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ronald_a
or is the only way to restart houdini?
Are you finding that restarting houdini actually fixes the issue?
ronald_a
in the renderstats it just says cuda error
Are you able to screenshot that for me? thanks
ronald_a
I am on window10 and my driver version is 546.01 (with 2x RTX A4500).
That driver is not within our recommended range.
https://www.sidefx.com/docs/houdini/solaris/karma_xpu.html#supported-hardware [www.sidefx.com]
https://www.sidefx.com/Support/system-requirements/ [www.sidefx.com]
Are you able to test with 546.33 (it'll be listed as a GeForce driver, but should be fine for testing)
thanks lots
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