I'm trying to make some underforest scenes with Carrara (latest update).
I have very regular crashes when rendering with HDRI background, GI, and lots of plants (eg. 4-5 different species with transparencies for leaves) , using multiple surface replicators.
Is there a way to predict when this memory "bug" will occur ?
This is very frustrating since it generally happens after 60-72 hours of rendering.
(quad core system with 2G ram and Vista)
thanks

 From your description, you are hitting the limitations of your system, not Carrara. Your scene render settings are using everything Carrara has. The one thing Carrara needs for a scene like that is tons of memory - 2G is not enough. 

Unlike programs like Photoshop, Carrara doesn't spool off rendering memory requirements to disk drives. Carrara can spool textures but that is different than the actual render calculations. 

By the way, you can crash out any 3D application by not having enough memory - C4D, Vue etc. Trust me on that. ;-)

Mark

The always advice too: clean the unused shader and objects before rendering, and close all opended windows (VM Room, Texture Room, Tree Room and other windows)... maybe you can low your view settings to get more memory t render too.

Quote -  From your description, you are hitting the limitations of your system, not Carrara. Your scene render settings are using everything Carrara has. The one thing Carrara needs for a scene like that is tons of memory - 2G is not enough. 

Mark

I made the stupid choice of a premade system, I will add 2 gigs of Ram but the limitation will come from Vista 32bits ...
It seems quite hard to find an Xp64pro version nowadays, notwithstanding the price.

If carrara was running under linux it would so simpler ...
YA

Quote - The always advice too: clean the unused shader and objects before rendering, and close all opended windows (VM Room, Texture Room, Tree Room and other windows)... maybe you can low your view settings to get more memory t render too.

I tried all this, reboot the computer, launch an empty C6, put the scene in the rendering batch and launch, it still crashes.
I think the problem comes from the amount of ram available, since the spooling to disk seems limited in C6 ?

I also have 2G ram and experience crashes with complicated render settings. I find that for anything I have done to date, 72 dpi always works. That is okay for web production, but for prints, not so good. I fuss with the render settings until I get the highest quality that will not crash.
If increased ram is the answer, I know what I am getting for christmas... (Hmmm... no, I already put a Wacom tablet on that list, birthday, maybe....?)

can you do a print screen from your scene? Sometimews crash happen with some Poser content... so deleting it will make the scene render. I can precise what kind of content can do that but I already have problems with scenes with a few objects, but because a "bad" content it crashes in render and sometimes in just saving it.

Using 8 gig with Vista 64 bits with Carrara 6,5 i can render some pre made scenes sold by Daz with hight definition (size) .With XP and 2 gig it was impossible without compromise on the size of file and settings .More memory is surely solution

GKDantas: You mention trouble with poser content. Have you ever had such trouble with the DAZ dog, V4 or dragon characters? I am using these now (all together) in an otherwise simple scene and have trouble with rendering at better than 72 dpi.

I don't think it's worth the time it to use Indirect lighting with lots of plants. You probably won't be able to finish the render. If you really need it up close, then render the background without it, set that as a backdrop and render the foreground with it.

Quote - I don't think it's worth the time it to use Indirect lighting with lots of plants. You probably won't be able to finish the render. If you really need it up close, then render the background without it, set that as a backdrop and render the foreground with it.

I just figured that I could do this :
uncheck the visible box for the objects in the foreground, make a render of the background ; paste as a picture, then render just the foreground, will the result be realistic enough, I'm concerned about shadows specificaly ?
YA

Well, sometimes you have to think a bit on then best way to do it. Plan ahead to see the where to separate the front parts from the back . This scene was done using that technique.

http://tinyurl.com/6qmt9p

This is a thing that we need to have in mind all the time: all great 3D artist do things in layers, sometimes using 3 of then: foreground, middle and background that is composed in a video editor or 2D editor... and lots of effects are post effects created outside the 3D software.

I agree, I have rendered the scenes that HowieFarkes has put together for Carrara and they are fairly complex with items.  There are some in his gallery that are pretty large.

His Gallery at cgsociety http://howiefarkes.cgsociety.org/gallery/
His Gallery on his own page http://howiefarkes.com/#_images/gallery/

This one was interesting
http://howiefarkes.cgsociety.org/gallery/559385/

100 instances of tree's with about 10,000 replications per instance

Quote - Well, sometimes you have to think a bit on then best way to do it. Plan ahead to see the where to separate the front parts from the back . This scene was done using that technique.

With 4Gigs of Ram everything works now a lot better...my vista sees 3,3 Gb. And apparently I cannot upgrade this OEM version to 64 bits !
Is there any way to organise objects in "layers" in Carrara just as we can do in Vue ?

Yves

You can use Groups in Carrara... just select what you want and hit CTRL + G to create a group.

Quote - I agree, I have rendered the scenes that HowieFarkes has put together for Carrara and they are fairly complex with items.  There are some in his gallery that are pretty large.

His Gallery at cgsociety http://howiefarkes.cgsociety.org/gallery/
His Gallery on his own page http://howiefarkes.com/#_images/gallery/

This one was interesting
http://howiefarkes.cgsociety.org/gallery/559385/

100 instances of tree's with about 10,000 replications per instance

Yeah, but notice I haven't set up many of those scenes with GI or Skylight. I fake it with a dome of spot-lights. Iit's faster and often times looks better than using skylight (plus I don't usually have to worry about "memory allocation" errors). The larger you render with Skylight the more likely you are to have your render fail, but with a skydome of about 30 spot lights I've rendered images of 8000x4500 pixels without issue.

For me whenever I am rendering one of Howies scenes and I have made changes to it then I will get a 'Mem Allocation Error', but I found a little work around it, so if I will save a New File, that is to maybe add a 1,2,3 or A,B,C to the backside of Howies Scene File Name, then I can render without Error at all and I have rendered a 7500x5625 pixel at 300 DPI for printing and hanging on the wall ;^D
Tyr It, it may help!!!