VFB saving issues & advantages

[fingerindustries]

I'm new to Vray and I am having a problem using the VFB! When I use the Vray VFB and render a large image (3500px +) once its rendered to the window I can't save the file and I get a ' Cannot save bitmap' error (whch is SO annoying after waiting hours for it to render!). If I render using the Max 9 VFB its fine and I can render huge files either to the VFB or just save straight to a file.
I'm aware the advantage of the Vray VFB is so you can tweak the colours after but its rather useless if you can't save it! I also know upgrading to a 64 bit system would help too, but its not a feasible option at the minute...

Any thoughts on why it fails to save and is there any real advatage in using the Vray VFB in the first place?

Cheers
Marcus

[instinct]

Well the color corrections are meant for previewing rather then actual Color Corrections. They are not saved if you hit the save button in the VFB. There are many advantages for using the VRay VFB like directly saving to multichannel EXRs, or disabling the memory framebuffer to save ram etc.

Regards,
Thorsten

[fingerindustries]

Thanks Thorston, but you've sort of highlighted one of the issues in that if I do disable the memory framebuffer I can't save the file to a tif (or any bitmap) file it has to be a raw file and having no understanding of vrimg files or 'multichannel exrs' (let alone how on earth to extract them all in the DOS prompt) its rather useless. If you know of any tutorial that helps this issue then do let me know (and i've looked!)

Cheers
Marcus

[Morne]

there are countless posts regarding that here. Just do a search.
Or just go here:
http://www.spot3d.com/vray/help/150SP1/vfb_index.html
there is all the info you need. It helped me out when I also didn't know much about it. Save to a vrimg file and you can convert it with the vrimg2exr tool they mention on that page. Then just open the EXR in photoshop.
With the new version of VRay you can apparently save directly to EXR from the VFB, but I haven't tried that yet. Just follow the step in the page I mentioned and you'll be just fine.

Kind Regards,
Morne

[fingerindustries]

Thanks Morne, i'll give that a go and see T

Thanks again

[fingerindustries]

As suggested I rendered out straight to a .exr file and opened it in Photoshop and its really washed out and a bit rubbish. Looking in the channels the RGB isn't Red Green and Blue; they are all greyscale variants - so what's going on here then?!

Cheers
Marcus

[rivoli]

it looks washed out because exr is a linear format, you can preview how it will look toggling the small "display colours in srgb space" button at the bottom left of the vray vfb. assuming you're working in 32 bit mode and haven't clamped the output, you can easily gamma correct the image with exposure in ps.
as long as the rgb channels go, they are supposed to be like that, greyscale channels that is (imagine them as mattes masking solid rgb colours). I think you can tell ps to show them coloured if you want, at least you can in ae.

[Jer25]

I just read the link and never knew about the "hidden" parameters before. Is there anyway to make them "un-hidden" for us that have no idea how to use max script?

I dislike how Autodesk has changed the way you access features like blow-up and region rendering.