View Full Version : using the cached framebuffer

07 July 2009, 03:55 AM
So I am trying to use the cached framebuffer in maya 2009 sp1a x64 through the ctrl_ghost shader. I have gotten this to work before in tests. But am now trying to use it on a real project and am having issues. And I really don't know what it is thats causing it

My render gets through the final gather calc just fine, then it gets to about 50% in the rendering phase and then just stops and says 'maya exited with status 1' and is done. Now it is making framebuffer files in the directory I specific, so I know it's working.

I'm just curious to know, has anyone here used this feature on a complex scene with success?

and on a sidenote. Whats the best render manager to use to automatically split up a render into smaller chunks and then automatically combine them?

07 July 2009, 09:01 AM
I cant speak for the ctrl.ghost geo shader, but I've made my own geo shader to change this attribute in mental ray, and we are currently using it on high demand productions just fine. I'm pretty positive that ctrl.ghost would be the same method I'm using, so either there's a bug with the caching method, which I'm yet to encounter, or more likely there's something wrong with your scene.

I'm not sure how much of a benefit cached framebuffers really gives, so if its causing you any issues, just turn it off and see what happens.

07 July 2009, 01:24 AM
does your scenes use BSP2 or regular BSP and do they have any proxies or assemblies?

just wondering cause mine does and the bsp2 and proxy thing has been breaking things all over the place for me

07 July 2009, 03:51 AM
Yes, I've used it with proxies, and all the time with bsp2.

Proxies are a piece of crap in 2009 tho... that could easily be your issue, I'd steer clear of them till they are properly implemented.

07 July 2009, 08:12 AM
Do you actually notice lower memory consumption with it turned on?

I'm rendering a image 4000x3000 big and I've tried it now with ctrl_ghost set to 0, 1 and 2. And also with no ctrl_ghost at all. And the memory consumption seems to follow the same sort of characteristic.

It starts at 700-800mb. From 1-20% it climbs to about 1.7 gb. And then from 20-35% it climbs to 8 gbs, starts flush my .maps repeadetly and then quits.

It doesn't seem like ctrl_ghost switch is doing anything at all. It does produce the framebuffer files in the directory I specify. And it produce larger files when the framebuffer is larger. So I know ctrl_ghost is registering and doing something. But it still seems to be loading the entire framebuffer into memory, or attempting to do this.

Is this frame buffer cached mode really intended to be used to render single pass large images? Or is it something thats supposed to be more when rendering animations with multiple passes? Cause I really don't think it's doing a single thing on my end here.

Has anyone done some more extensive tests on this feature? Cause I tried it with a bunch of cubes and 12,000x12,000 pixel image and it seemed to work. But now, using it on a real scene with FG, reflections and all that, it seems to be doing nothing.

07 July 2009, 09:09 PM
Based on what the documentation says, and personal experience, I dont think this has a huge impact on memory, its intended for large images, and is significantly faster when saving out the framebuffers at the end of rendering.

08 August 2009, 10:44 AM
Well thank you for your replies so far.

But it turns out. In my scene I had a maya phong material plugged into the diffuse slot on a mia_material_x by accident and for some reason this made my memory exponentially increase when trying to render it.

But now with that fixed. It rendered it. 4000x3000 in one go.

Although at the end it said

error: scene failed to render.

//maya exited with status 210

but it saved the .exr before that, so I got the render...

08 August 2009, 08:07 PM
Maybe you should tell us what you are rendering and how many polygons you have. Under normal circumstances you can render 10 million polys in 8000x5000 with no problems.
Your description of the problem is very vague... The most important point is: What hardware do you use?!

08 August 2009, 01:39 PM
i got the thing all fixed. Its actually working perfect now

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