Problem rendering at high res

[markf]

I have a scene I'm rendering. My "standard" Vray settings for final image are:

 

3000p x 2000p

DMC sampler - 2,5, clr thresh .005 (use dmc sampler thresh un-checked)

primary - IR map medium preset with HSph Sub 20

secondary - Light Cache 1000.

 

I can render up to 2000p ok. If I go to 2500 the rendering hangs or crashes on a stage called "pre-filtering light cache". I've tried hiding some of the memeory intensive stuff like the fur on the grass and some onyx vray proxy trees, but that doesn't help. I'm watching the RAM usage in the task manager and I don't seem to be running out of RAM with this lock up/crash happens.

 

Can anyone help me with figuring out how to get this to render at 3K? That's the resolution I render everything else to with out this problem. Thanks in advance for any suggestions or guidance.

[jophus14]

Save render as a VRImg through Vray Frame Buffer and re-render. There are tons of threads regarding how to do this.

[markf]

Joseph,

 

Thanks for that idea. I will try it. I read the Chaos help about vrimg and have looked at some of the threads here. One question, if I render out as .vrimg how do I open that file format in photoshop? I'd need to ultimately save as .jpg.

 

Thanks!

[Crazy Homeless Guy]

...also, go ahead and pre-calculate the lighting solutions at whatever you know it will work at, and make them read from file. This is easier than trying to figure out how to adjust them for a larger resolution.

[jophus14]

Joseph,

 

Thanks for that idea. I will try it. I read the Chaos help about vrimg and have looked at some of the threads here. One question, if I render out as .vrimg how do I open that file format in photoshop? I'd need to ultimately save as .jpg.

 

Thanks!

 

Here's a quick How-To:

 

When you open the VRImg to OpenEXR Converter it'll look like this: C:\Program Files\Autodesk\Viz2007 or Max\Plugins\tools>

 

Then you will type:

 

vrimgexr(space)C:\name you want file to be.vrimg(space)C:\name you want file to be.exr(space)-sRGB

 

Example: vrimgexr C:\InteriorHall.vrimg C:\TestRender.exr -sRGB

 

When the file is finally saved to the destination that you picked it'll show up as a EXR file. Double click this file and Photoshop should open. Resave the file as a Tiff or Jpeg once in Photoshop.

 

If anyone sees anything wrong or indifferent with the way I explained this method of using the OpenEXR, please add to this post.

 

It's quite simple after you do it once.

Edited October 15, 2008 by jophus14

[markf]

Travis,

 

Are you saying I would save the IR map and LC to files at say 2000pixels wide. Then I would use those pre-calced files and render at 3000pixels?

 

Joseph,

 

I'm going to try what you suggest. This shows my total lack of knowledged of this but, wher e do I find the VRImg to OpenEXR Converter?

 

Thank you both for your help!

[Crazy Homeless Guy]

Travis,

 

Are you saying I would save the IR map and LC to files at say 2000pixels wide. Then I would use those pre-calced files and render at 3000pixels?

 

Yep. Standard practice. I often double the width that I do prec-calcs at. This is true of both Vray and Mental Ray, and I am assuming most GI engines.

[markf]

Travis,

 

That's very good info. I have not worked with saving the IR and LC files before but am trying it now. When do you re-calc/re-save the files. Only if you change a light? How about if you chnage a material or some geometry?

 

Thanks very much for your help with this.

[Crazy Homeless Guy]

I would always re-calc before doing a final render. You can change materials, and to some extent, lighting and geometry, but the solution becomes less accurate, or sometimes down right unusable.

[markf]

Travis,

 

That's a neat trick! It seems to be working for me. I had to change a bunch of Vray displacement to bump mapping and get rid of quite a few onyx tree Vray proxies. If I render at 2K and save the IR map and LC files, then render at 3K using the previously saved files it works (most of the time ). I hope to have time to try the vrimg file strategy and see how that works.

 

It isn't that big of a scene - 750,000 faces. It renders at 3K in 1hour 30 min. I have a fairly large section of grass in the foreground that I'm using Vray fur on. I suspect that's the issue.

 

I'm going to post the scene in the WIP section later today.

 

Thanks for your advice, it really helped!

[Crazy Homeless Guy]

Travis,

I hope to have time to try the vrimg file strategy and see how that works.

 

Depending on your needs, you might want to use both at the same time.