Problem extracting VRayZDepth channel from vrimg

[re:FORM]

I'm not sure what I'm doing wrong, but I can't seem to extract my z channel from the vrayZDepth channel from the vrimg file. It appears to be a 'float' channel rather than a 'rgb' channel.

vrimg2exr pic.vrimg -half -channel VRayZDepth

Any ideas where I'm going wrong?

[sv]

do you also need to specify the output?
i.e. something like:

vrimg2exr pic.vrimg pic_zdepth.exr -half -channel VRayZDepth

(from memory - might not be 100% right)

[Aldaryn]

It appears to be a 'float' channel rather than a 'rgb' channel.

Yup, Z should be a float channel. When it comes to outdoor scales, it's good to have a hdr Z depth. However, the last time I saw the manual, there was no Zdepth channel name in the accepted values for name attribute. Note, that I've never tried to extract Z from a vrimg file, for other reasons, we always had the Z saved as a render element separately.

Do you get any error messages, or something?

best regards,

A.

[re:FORM]

yep I do get an error message. It says "Specified channel name "VRayZDepth" not found or channel is not RGB channel in .... "
It makes me think there should be another flag to use to extract an rbg image from a float channel.

I assume I am using the correct channel name?!
When I use vrimg2exr with the -info flag, it returns the "VRayZDepth" channel as type float, and alias ZDepth. I've tried both "ZDepth" and "VRayZDepth" as possible channel names (case sensitive too).

[instinct]

Just out of curiosity, why dont you render to exr directly instead ?

Kind Regards,
Thorsten

[re:FORM]

hmmm.. I was writing an explanation of what was making me work with vrimg files when I realised the fundamental problem I had was that for some reason I couldn't load 32-bit realpixel exr files into photoshop. I found that saving them out as vrimg files, then extracting the full float 32-bit data to exr did work.

I'd also been experimenting with outputing alot of channels for compositing in post and then you come across the issue of too much ram being addressed to handle all the channels in the vfb that you can avoid if you render direct to vrimg.

I'm working on a lowly 2gb ram laptop at the moment, and the project is easily hitting 3.5gb when rendering at 3000px wide res without even taking into account additiona render elements.

[instinct]

Well you can save out tiled exrs just like vrimg without max's standard save. That also outputs Half EXRs instead of full float ones and works like a charm. And you get the same memory advantages as with vrimg during rendering.

Kind Regards,
Thorsten

[vlado]

I have an updated version of the vrimg2exr converter that can extract the z-buffer, velocity, render id and other channels as RGB equivalents, if anyone is interested...

Best regards,
Vlado

[re:FORM]

Hi Vlado,
That sounds like just what I need. Can I get a copy?

Nice one! Thanks.

p.

[gfa2]

I have an updated version of the vrimg2exr converter that can extract the z-buffer, velocity, render id and other channels as RGB equivalents, if anyone is interested...

Best regards,
Vlado

I'm having the same problem as re:FORM today...I thought i was loosing my mind cause I couldn't that channel out of the vrimg. I'd love to get the new converter too.

@ instinct: what do you mean by tiled exrs?

[vlado]

You can download the updated vrimg2exr here:

http://www.spot3d.com/vray_downloads/vrimg2exr.rar

In this version, you should be able to use the -channel option with zdepth, velocity, renderID channels etc.

Best regards,
Vlado

[gfa2]

Perfect...thanks.

[re:FORM]

Excellent! Thanks Vlado,

I just wanted to check also, when you save from the vfb to EXR do you only ever save at 16-bit float? I can't seem to load 32-bit float into either photoshop or after effects.

[vlado]

Do you mean if you specify .exr as the raw image output, instead of .vrimg?

Best regards,
Vlado

[re:FORM]

No sorry, I mean when you just either save from the vfb, or use the standard vray save to split render channels.