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H11 / Mantra and memory usage.


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Hi guys,

I need help :(

How can I reduce the amount of memory mantra needs to render a scene, or at least figure out what is eating up all my Ram. I'm rendering at 1080p a scene that uses a lot of instances, and mantra is peaking at 11GB usage. Which is ok on my workstation, but the render nodes on the farm only have 8GBs.

So I need to get it back down under 8, but I don't know how to do that.

One idea is to render different objects and comp it all together, but if I make all the other objects phantoms then won't they still require the same amount of Ram? (I'll have to run tests).

Any advise would be great.

Thanks,

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ok, after checking memory usage. It turns out that mantra is only using 6.7Gbs and Houdini UI is using another 2Gbs. So I think I'll be ok on the farm after all.

I will try to break it down, and render different objects in different passes. Maybe replacing some objects with low res proxies and such.

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Hi guys,

I need help :(

How can I reduce the amount of memory mantra needs to render a scene, or at least figure out what is eating up all my Ram. I'm rendering at 1080p a scene that uses a lot of instances, and mantra is peaking at 11GB usage. Which is ok on my workstation, but the render nodes on the farm only have 8GBs.

So I need to get it back down under 8, but I don't know how to do that.

One idea is to render different objects and comp it all together, but if I make all the other objects phantoms then won't they still require the same amount of Ram? (I'll have to run tests).

Any advise would be great.

Thanks,

if you're instancing, be sure to delayed load in all of your instances (and anything else you can for that matter)

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if you're instancing, be sure to delayed load in all of your instances (and anything else you can for that matter)

thanks, i think that will help. It won't be hard to convert all my instances to use delayed load.

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I want to remind, that you should use only rat texture format, also take a look at Opacity Filtering in mantra ROP. If there is no transparent objects in your scene, set it to "Closest Surface" in some cases it can improve performance.If possible, try to NOT use displacement on instances.Make sure that you using Depth Mapped shadows where it's possible (as a general rule - reduce raytracing as much as possible). In case of motion blur, increase Motion Factor, to reduce dicing of blurred objects. Also play with KDE-Tree Memory Factor, and tile size.

Hope this should help. Good luck. B)

Edited by Stalkerx777
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Also, which build are you using?

 Wednesday, March 2, 2011
Houdini 11.0.673: Disabled displacement shader output for the mantra surface material unless displacement map or displacement noise are enabled. This change will speed up renders using the mantra surface material without displacements. 

Not only will it speed up renders, but also save on memory when dealing with instances.

If you are raytracing all the geometry will be kept in memory until the render is complete.

Example of setting up delayed load instancing:

http://www.peterclaes.be/blog/?p=34

file:

http://www.peterclaes.be/blog/wp-content/uploads/2010/08/delayed_load_instancing_01.hip_.zip

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thanks guys, that's a lot of tips.

I'm using build 733, and yes I have displacements on instances but I think I disabled real displacements and I'm just using a noise function as a bump map. Will that cause me problems? I'm also not using RAT. I know there is a command line tool to convert images to rat, but I keep forgetting to use it. I should write a python tool that will aid in rat conversions.

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Also, which build are you using?

 Wednesday, March 2, 2011
Houdini 11.0.673: Disabled displacement shader output for the mantra surface material unless displacement map or displacement noise are enabled. This change will speed up renders using the mantra surface material without displacements. 

Not only will it speed up renders, but also save on memory when dealing with instances.

If you are raytracing all the geometry will be kept in memory until the render is complete.

Example of setting up delayed load instancing:

http://www.peterclaes.be/blog/?p=34

file:

http://www.peterclaes.be/blog/wp-content/uploads/2010/08/delayed_load_instancing_01.hip_.zip

Shouldn't that be controlled by the switch of true displacement? That's probably why my custom shaders started rendering funky.

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