Mental Ray geometry cache

[Maximus]

Hm hello guys,

i was wondering..i saw on 3ds max there is an option to cache geometry so it doesnt get loaded everytime you hit render of course if you dont modify add or remove geometry, this is a speed up thing.

I was wondering if XSI have this, it already does under the hood? I couldnt find any option to turn on/off.
I have a 3.5 mil poly scene and everytime i make some change it always seem to take the same amount of time to start rendering.
Anyone have some info about how MR handle geometry caching in Softimage?

[Tekano]

yeah course we have it - they are called Stand-ins. take a look at the manual they are all explained... but simply in the Render menu Export>>Selected Objects then Get>>Primitive>> Stand in and connect it up to the exported MIA object you have just created.

simples!

[origin]

mr in max is like vray beta in xsi. It needs to export scene data to renderer. I believe xsi's mr has (or had...) direct access to xsi scene data therefore export is not necessary. Thats theory but in practice there is always some delay every time you make some changes on heavy scene.

[Tekano]

Hi Origin,

Ive found there is most definately a difference in how XSI (or Mental Ray) is rendering a scene with standin's or not. Yeah I know its 'supposed' to be doing stuff under the hood, but for example I have a test scene 2011 with over 10,000 instanced characters with hair - rendering will not work as default, the Ram fills up in minutes and crashes but if I make the stand-ins first the scene renders super quick and memory stays around 4 - 6 Gb

[Maximus]

Hello, thanks for answer but i guess i didnt explain myself in a good way or i'm missing something here.

I'm speaking of a feature in Mental Ray wich i dont understand if:

1) is working
2) is not working because it needs to be activated
3) it is not implemented

I'm not speaking about Stands In (proxy) this is another story totally.

Softimage:
I have 10 objects for a total of 4 milions poly in my scene, when i drag render region mental ray hangs for seconds before the actual FG or render starts. Then i close the render region and drag a new one, again Mental Ray hangs for seconds before it starts rendering.

3ds Max:
I have imported the scene, 10 objects for a total of 4 milions poly, when i launch the render mental ray hangs for seconds before FG or render starts.
In the render manager here:



I turn the check "Geometry Caching" Enable, relaunch render and it hangs as usual but only because it needs first to read geometry and cache it, after this if i dont alter the geometry (add, remove geometry) and launch the render it is instant.

My question is, is this feature broken inside Softimage? Does it do the geometry cache under the hood? Is this feature missing?
Beacuse it is frustrating to say the least to work like this, anyone know a way to enable this feature?

Stands in are not a solution because its even more time consuming than just waiting the time Mental Ray spend to cache geometry everytime.


Thanks

Max

[Mathaeus]

Hello, thanks for answer but i guess i didnt explain myself in a good way or i'm missing something here.

I'm speaking of a feature in Mental Ray wich i dont understand if:

1) is working
2) is not working because it needs to be activated
3) it is not implemented


My question is, is this feature broken inside Softimage? Does it do the geometry cache under the hood? Is this feature missing?
Beacuse it is frustrating to say the least to work like this, anyone know a way to enable this feature?

Stands in are not a solution because its even more time consuming than just waiting the time Mental Ray spend to cache geometry everytime.

Max

Hi Max,

as far as I'm understand, none of three. As Origin already said, SI uses a different system called 'shared memory', where you get all options of geo cache automatically - so there is no need for caching (theoretically). Let's say, Max is running on gasoline, XSI has a Diesel engine (or reverse) - you can't expect the same switches in both, even they looking the same, and they are product of the same factory. AFAIK, just this 'shared memory architecture' was a selling point of early XSI, even our XSI Foundations.

Obviously, something doesn't work as expected in last few years - why is that, is it everything related to 'shared memory', is it something else on the road.... who knows.

[origin]

Increase mesh splitting factor (1 to 50,100,300...)
tested only with 8 4million animated buddas
instant render after 1st render, can change srt of objects (instant) materials, skip to frames etc

will try to test max2011 later, now it hanged few times on 8million sphere

[Maximus]

Increase mesh splitting factor (1 to 50,100,300...)
tested only with 8 4million animated buddas
instant render after 1st render, can change srt of objects (instant) materials, skip to frames etc

will try to test max2011 later, now it hanged few times on 8million sphere

I'm sorry, what you suggested didnt have any effect in my scene, at all, tried splitting factor from 0.1 to 3000, always the same render hang.
I have 1 object only now wich is 3.7mil poly on a plane, thats it. Mental Ray hangs on launching render no matter what i do.
I have 24gb ram, I7 990xtreme, oCZ ssd hard disk.

What machine do you have? Are you using soft 2012sp1? There is something really going wrong here if it works for you.

Using Softimage 2012 Sp1 x64bit.

[origin]

sorry to hear that, care to share a scene?

seems xsi is doing same thing like max, caching geo under the hood, at least with mesh splitting factor being high.
Adding some mesh-invalidating deformers like bend and moving thru frames makes mr hangs for first render (next is instant)
only few things differ
-max is recaching all geometry even if only one is invalid (eg one animated bend on only one of eight budda meshes)
-max is hanging for a while after clicking cancel
-max export time is 3 times longer

tested only on 8 budda scene, 32million polys

will try to do some more test on weekend

[Maximus]

Well, i've tried to play with the mesh splitting factor with no success at all, its like nothing happens if i rise that parameter.
Went up till 100000 rendering 4 times each render, always the same, there are like 10/15 seconds hang on loading geometry after i hit preview button.

here is the scene

http://www.2shared.com/file/6WdcXgmS/00_online.html

i've tried to merge all objects into a single mesh but no luck with this either, i've also duplicated the object and went up to around 5 mil poly, tried again with mesh splitting factor, nothing.

clueless.

OT: Also i finally can confirm there is a problem with final gather, just checked mailing list, hurray for Mr!

http://groups.google.com/group/xsi_list ... 8e66066557

[origin]

allright, I didnt use fg :/

//edit:
but your scene starts rendering instantly here...either render preview/render region 2012 sp1

maybe there is a problem with >6 (12ht) cores processors?...i'm on i7 4cores

[Maximus]

Thanks for help Origin, have no idea what is wrong.

Anyway there is really a big difference with 3ds max, i've imported the model subdivide as a single mesh into 3ds max, the first render it took a bit to convert geometry, when i activated the geometry cache it took the same and cached geometry, then i've rendered again and it was instant.

In softimage i really have to wait 10/15 seconds before i start to see a bucket starts to render, no matter mesh splitting factor or anything else.
i'm totally clueless.

[Maximus]

allright, I didnt use fg :/

//edit:
but your scene starts rendering instantly here...either render preview/render region 2012 sp1

maybe there is a problem with >6 (12ht) cores processors?...i'm on i7 4cores

Im sorry, just to understand it, what you mean "it starts rendering instantly"
The very second you hit preview/render region, you start to see bucket rendering? Because that is what happens to me in 3ds max after i activate the geometry cache, but not remotely in Softimage, i have 10 seconds to say the least before i see the first bucket, even if in the script editor (i've checked) stuff is happening but it doesnt refresh the preview render window before that time i said.

[origin]

Yes, no wait time with scene you attached. I hit preview and after 0 sec I see buckets flying around image...

[Maximus]

Yes, no wait time with scene you attached. I hit preview and after 0 sec I see buckets flying around image...

Damn it, this is getting me crazy now...i have no idea where to look for solve this thing..
Thanks again

[Lord Futzi Voldemort]

Yes, no wait time with scene you attached. I hit preview and after 0 sec I see buckets flying around image...

Damn it, this is getting me crazy now...i have no idea where to look for solve this thing..
Thanks again

There´s a setting in Preferences>Rendering which could have an influence here: "Empty Rendering Cache".
See that only "After Rendering a Pass" is checked. This is the only caching option I know.

Achim