Hi everyone i am rendering in houdini and in my task manager it says that only 1.5gb is been used out of 4gb. How do i allow it to use all RAM available ?

Any help appreciated

ha ha. It's funny that you ask that since typically we profile the renders and optimize as best as we can to REDUCE the amount of RAM required to complete the render.

Generally speaking, you want your renders to occupy as LITTLE ram as possible – if you are looking for a ‘go faster at the expense of using more RAM’ slider, I don't think such a thing is available.

Best,

G

keyframe
Generally speaking, you want your renders to occupy as LITTLE ram as possible – if you are looking for a ‘go faster at the expense of using more RAM’ slider, I don't think such a thing is available.
Best,
G

Bigger buckets?

You are right. Bigger buckets will undoubtedly take up more RAM.

Wouldn't necessarily go much faster though.

G

If you're using Displacements, you can add and turn on Precompute Bounds which will (often but not always) speed the render and use more RAM.

If you're raytracing at all, you can add a Rendering Parameter called “KD Tree Memory Factor” and increase it.

This is a general mem-vs-speed tradeoff.

Shame they aren't documented:

Houdini name vm_octreestyle
IFD name rendererctreestyle
Default (1)

Tunes ray-tracing acceleration structures. The default is usually reasonable and there is typically no reason to change the value.
Houdini name vm_kdcrossover
IFD name renderer:kdcrossover
Default (100)

Tunes ray-tracing acceleration structures. The default is usually reasonable and there is typically no reason to change the value.
Houdini name vm_kdcostratio
IFD name renderer:kdcostratio
Default (1)

Tunes ray-tracing acceleration structures. The default is usually reasonable and there is typically no reason to change the value.
Houdini name vm_kdmemfactor
IFD name renderer:kdmemfactor
Default (1)

Tunes ray-tracing acceleration structures. The default is usually reasonable and there is typically no reason to change the value.

And there you have it.

Learn something new everyday!

So, errrr, anyone have ANY experience tuning those settings that might be able to shed some light on what they do, and in what context we might want to tweak them?

G

keyframe
And there you have it.

Learn something new everyday!

So, errrr, anyone have ANY experience tuning those settings that might be able to shed some light on what they do, and in what context we might want to tweak them?

G

The documentation I found said: “The default is usually reasonable and there is typically no reason to change the value.”

I don't think you want to tweak them.

I understand that you want it to use as little RAM as possible which means it renders faster, but all the RAM left over is not been used ? to take advantage of helping the process …???

Lyonz
I understand that you want it to use as little RAM as possible which means it renders faster, but all the RAM left over is not been used ? to take advantage of helping the process …???

You don't need to use 8 litres of water to make a single hard-boiled egg.

Fair enough but how do you turn up the heat to cook it quicker ?

MOAR HOT PLATES~!

G

Using more memory for a simple object could have the side effect of overflowing your CPU's L2 or L3 cache (which is only 2 to 12MB) - in which case computation will be stalled by continuous memory requests. In that case, you'd actually want to reduce the size of the constructed data structures for better performance. It really is a difficult balancing act between memory usage and computation.

Had to ask cheers for everyones replys.

keyframe
You are right. Bigger buckets will undoubtedly take up more RAM.

Wouldn't necessarily go much faster though.

G

I've noticed small, but visible, increases with speed on multi-core systems, as with bigger buckets, less time is spent on cores waiting for another spot to work on, and more time is spent on rendering. Although if the scene is really complex it won't matter much, and as you said, it will use more memory.