Hi res unstability

[cristoforo]

I love vray.....but am VERY disappointed with it's stability to produce hi res renderings. I am trying to render an image at 4200x2562 with dispalcement on the grass and HDRI for environement lighting and reflections....but the Max crashes! Unfortunately the view needs to be printed tomorrow...which probably will not happen. Now what do I tell my boss?!?!? I tried all suggestions for displacement (tesselating, increasing edge length) then turned off displacement to find the same problem. Not the displacement. I reduced the HDRI map.......then turned it off to find that the HDRI is not the problem. The trials all render fine at 640x480. I have glossy reflections......do have to do something special here? I also turned on dynamic memory.....no luck. I am using Irradiance map and light cache. The computer is a Pentium 4 3.2 Ghz 2 Gb Ram. I feel helpless here!!! Here is the image:

[RErender]

here are some keywords for you:

Proxies
3GB Switch
vrayimage
slices

[egz]

Max crashes because it runs out of memory, but there is a trick to render super hires:

To save memory while rendering you do the following:

1. Max always creates its framebuffer no matter what, even if it doesn't display it. This of course wastes a lot of memory. So set the rendering size in the Common Parameters rollout of the Common tab to something tiny, like 20×20 pixels. This will use very little memory.
2. Now scroll down to the bottom of this rollout and uncheck Rendered Frame Window. You have now disabled the max virtual frambuffer as much as possible.
3. Switch to the Renderer tab, and open the VRay:: Frame buffer rollout.
4. Check Enable built-in Frame Buffer
5. Since you probably want to render more than 20×20 pixels uncheck Get resolution from MAX and set the output resolution you want.
6. Uncheck Render to memory frame buffer. This way you won't use up all your memory to store the image while rendering is in progress.
7. Enable Render to V-Ray raw image file and set the filename/path you want.

You should now be able to render huge scenes (We've rendered over 14k on a 2GB system without problems).
When the rendering is finished you can use the View image file tool in 3ds max (file menu) to load the .vrimg file and save it as a tiff or tga or whatver you want.

You won't see any frame buffer while the rendering is in progress, but at least the image should render.

[cristoforo]

In this file I have nothing to proxy. Does the 3 GB switch make any difference if I only have 2 GB Ram? Vrayimage?? Slices??

[cristoforo]

Interesting Egz....I will have to give it a try. For now I reduced to 3600x2247.......it seems to be going OK. Tomorrow I will have to give your suggestions a try. Do not want to risk now...........just want to go home!!!

[egz]

Also, remember to lower your irradiance map settings when you increase the resolution for final render, unless you are already using a saved map.

If you render 640x480 and 4200x2562 with the same irradiance map settings, your irradiance map for the hires rendering will need as much as 35 times more memory.

[DaForce]

yeah your IR map setting shsould be very low for a render of that size.

Also turn on dynamic memory and then keep raising the MB limit until it crashes, then back off 100mb and render.
It will render slowly but if its a memory problem this will definitly help you.

[jujubee]

Could be my imagination - but didn't Vlado mention something about rendering to Hard Drive in another post recently?

[DaForce]

Thats what the vrayimage is about.
You render straight to the file

[cristoforo]

This raw image file is not working for me. I am doing a test to make sure it works before launching the final version. I followed all the steps as written above, but in the end I have a TINY image...........seems to be rendering at 20x20 and not the 500x500 that I put in the the output resolution of VRay frame buffer. HELP!!!!!!

[cristoforo]

Can I use this feature with DR???

[cristoforo]

The image size is following the output that I type in the Common tab and not the Vray frame buffer. For examlple: If I type 400x400 in the common tab and 500x500 in the frame buffer I get and image of 400x400 on a black background of 500x500.

[Clifton Santiago]

My strategy for rendering hi-res images with memory problems, besides several of the things mentioned above, is to netrender to backburner with Split scanlines (render stripes). Set the strips to really small, 5 to 10 pixels each. This way the machine(s) will only be using the memory necessary to calculate the strip it is dealing with.

If using this method with IR and QMC you will not need to pre-render the IR pass. All machines should calculate everything close enough to be seamless.

However with LC, you will need to pre-calculate it on one machine, save it, and re-use it on the render stripes pass.

This method will take longer to render, but it should allow your machine(s) to power through.

And as bad as it sounds, if all else fails, archive the file, find a big architectural visualization company that has Vray, and have their beefier systems power through it. I had to do that once and it worked well.

[cristoforo]

In the end, hi res really is not the problem here.....the same file I was not able to render at 1800x1200.....the computers were still running out of memory. I had to turn off the nice glossy reflections on the pavements. Is there some secret to using glossy reflections?

[Clifton Santiago]

I had images I had to render at 4000x2000 px and I could only get them to render at 200x100 because of memory errors!

The way I fixed it was to half the resolution of the HDRI, and set the pavement glossy reflections to "use interpolation". Also, set reflect/refract in global switches to 2. If you have glass behind glass the refraction calcs will kill your memory. I made the second layer of glass opaque. I proxied all my 3d people and turned on dynamic memory, set pretty high (1.5 Gb I think). And even though I only had 2 Gb of RAM, I enabled the 3 gig switch to allow more available memory usage. And then I strip rendered in backburner.