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bigdog
08-26-2005, 04:00 PM
This sounds like a total nubee question to ask ( which I am not) but how do you render 16bit images from with Mental ray for maya. The tiff16 and iff16 options are not availiable and I have tried changing the Data type to 4x16 in the Primary Framebuffer section of the render globals and rendering tifs and iff.s no luck.

Please help.

BD

DiGiman
08-26-2005, 05:45 PM
If you've changed the framebuffer, then it is rendering 16 bit images. The problem is that it won't render/display the images in the render view. So the batch renderer is the only way to get 16 bit images. Personally, I prefer the command line renderer.

bigdog
08-27-2005, 01:17 AM
Thanks for the reply. I am rendering with the batch renderer, but still no 16 bit. I can get 16bit from the Maya renderer and 32 bit from openexr but no 16bit from Mental ray. I wouuld love to know what I am doing wrong.

BD

bigdog
08-27-2005, 01:20 AM
I am selecting tif from the image format in the Common Dialogue and RGBA (Short) 4x16 Bit from the framebuffer. Is there anything else I need to set? Do I have to specify another file format in the batch render command with the -of switch?

Cheers
BD

jeremybirn
08-27-2005, 01:58 AM
I don't know what file format you are using, if you render .tif files, it seems to render 16-bit or 32-bit just fine according to framebuffer settings.

-jeremy

bigdog
08-27-2005, 03:11 AM
Thanks again for the reply. This is driving me nuts. I have tif selected in Image Format, and RGBA (short) 4x16 selected in the framebuffer. Rendered via command line but still no 16bit. I have attached a file, very simple camera, light, ball. Could someone check they are getting 16bit images from it . I will be forever greatful.

Strangely I can get a 16 bit image if I specify an output pass in the camera shape node ( new to Maya 7 I believe) but that does not work with renderpasses etc.

Thanks

bigdog
08-27-2005, 06:20 AM
Got it sorted. I had to select tif uncompressed as file type. I Could swear I tried that combination before. Anyhow, thanks jeremy and DiGiman for the replys.

BD

FrodeMohrsen
03-23-2006, 04:13 PM
I have the same problem.. I use combustion as a composing program, and when I render uncompressed tiff from maya mentalray, combustion only shows the upper half of the image, it's very very strange. Photoshop does'nt seem to have this problem though. I realy realy need to use 16bits images for zDepth in combustion, and as far as I know, the only way to get 16bit images from mentalray is through the uncompressed tiff fileformat.. Does anyone know of any other formats that can store 16bit pixels and also be stored from a mentalray rendering?

nikiatanasov
04-29-2006, 03:07 PM
Hi guys, I have the same problem. The only way I'm achieving 16bit file is with Uncompressed TIF but Digital Fusion opens the upper half only!?
In Mental Ray reference manual is told that a 16bit file formats can be IFF, RLA, TIF... etc.
I gues that there are 2 options, have to be done somethink weird in maya or this is a BUG?
How you guys solve that?


With Regards,
Nikolai Atanasov

pixlix2
04-29-2006, 04:57 PM
I'm not sure about the tiff problem but I've used 16bit iff sequences (framebuffer: 4x16 short) succesfully in fusion and in combustion. You could probably try the sgi format, too.

But there is another thing I wanted to ask:
Could someone explain the difference between the framebuffer settings
RGBA 4x16 (short) and
RGBA 4x16 (half)
?
Many thanks!

FrodeMohrsen
04-30-2006, 06:00 PM
Found a format that solves this problem, when it comes to maya and combustion atleast. OpenEXR is ILM's own HDR format, and supports up to 32 bit pixels, and is rendered without "problems" from mentalray in maya, and creates no artifacts in combustion.

jeremybirn
05-01-2006, 09:35 AM
But there is another thing I wanted to ask:
Could someone explain the difference between the framebuffer settings
RGBA 4x16 (short) and
RGBA 4x16 (half)

(half) = Half Floating Point. So it stores floating point values, that could be HDRI, it could go above 1 or even below 0. An ordinary single-precision floating point value is 4 bytes, half floating point sacrifices some accuracy (that you usually wouldn't need) but fits floating point data into only 2 bytes.

Regular 16-bit an't store over-exposed values, so if a region is overlit and clipped into pure white, you won't be able to recover the texture and detail in that area when you reduce the brightness, the way you could with floating point. (Regular 16-bit only improves the precision compared to 8-bit, it doesn't store an expanded dynamic range.)

All your software compatibility issues need to be checked again if you switch to any kind of floating point data. In general if something supports HDRI and reads the OpenEXR format, you ought to be able to use (half) and enjoy the benefits of high dynamic range files without a major increase in file size.

-jeremy

pixlix2
05-04-2006, 07:26 AM
Many thanks for this explaniation, jeremy, this was really helpful.

Recently I rendered a short animation which had some small over-exposed areas and I was wondering why the color was clipped although I used 16bit (short). Next time I will try half floating point and see how it turns out.

Many thanks

nikiatanasov
05-06-2006, 11:36 AM
Hi, I've tested with IFF, SGI, RLA and TIF. With all these formats I've tryed with
4x16(short);
4x16(half);
even with 4x32(float);
In mental ray manual is told that these formats are 16bit compatible.
And the result is allways 8bit IFF, RLA, SGI.
with Uncompressed TIFF the 4x16(short) works, but this format can be opened only by PhotoShop :( soo its unuseful for compositing a sequences.

Somebody that know how to output 16bit per channel SGI with Mental Ray under MAYA 7.0 ?
And witch software can be used for compositing OpenEXR format?

10x in advance

jeremybirn
05-06-2006, 01:54 PM
Hi, I've tested with IFF, SGI, RLA and TIF. With all these formats I've tryed with
4x16(short);
4x16(half);
even with 4x32(float);
In mental ray manual is told that these formats are 16bit compatible.
And the result is allways 8bit IFF, RLA, SGI.
with Uncompressed TIFF the 4x16(short) works, but this format can be opened only by PhotoShop :( soo its unuseful for compositing a sequences.

Somebody that know how to output 16bit per channel SGI with Mental Ray under MAYA 7.0 ?
And witch software can be used for compositing OpenEXR format?

10x in advance

I don't know. I actually had better luck with Maya 6.5 in rendering HDR .tiff files.

Maya 7 seems to write out files that no other program can open.

Maybe someone who's had better luck than me will answer you. :)

-jeremy

pixlix2
05-07-2006, 09:12 AM
hi dickagm,

do you use batch rendering? I think the render view just throws away the 16bit data...

nikiatanasov
05-08-2006, 02:54 PM
Hi all, thanks for replying.
I have found a friend with maya 5.0 and I've done a test.
---------------------------------------------------------------------
In Maya 5.0 rendering with mental ray all formats work fine :) I've tryed:
4x16(short)
*.IFF -> success 16bit
*.TIFu -> success 16bit
*.SGI -> success 16bit
4x32(float)
*.TIFu -> success 32bit (floating point)
all these files are opened in Digital Fusion4.04c without problem.
---------------------------------------------------------------------
the same test in Maya 7.0
All files are outputed as 8bit except TIFu but it does not open in Digital Fusion :(
---------------------------------------------------------------------
Are the other peoples have the same problem with maya 7.0 or this is my local problem?
Can this be a maya 7.0 bug? But I can't imagine that there's official version with major bug like this? How the other studios are handeling this? Is updating to 7.0.1 fixes that ?

sorry for English
and thanks in advance :)

jeremybirn
05-08-2006, 03:33 PM
Hi all, thanks for replying.
I have found a friend with maya 5.0 and I've done a test.
---------------------------------------------------------------------
In Maya 5.0 rendering with mental ray all formats work fine :) I've tryed:
4x16(short)
*.IFF -> success 16bit
*.TIFu -> success 16bit
*.SGI -> success 16bit
4x32(float)
*.TIFu -> success 32bit (floating point)
all these files are opened in Digital Fusion4.04c without problem.
---------------------------------------------------------------------
the same test in Maya 7.0
All files are outputed as 8bit except TIFu but it does not open in Digital Fusion :(
---------------------------------------------------------------------
Are the other peoples have the same problem with maya 7.0 or this is my local problem?
Can this be a maya 7.0 bug? But I can't imagine that there's official version with major bug like this? How the other studios are handeling this? Is updating to 7.0.1 fixes that ?

sorry for English
and thanks in advance :)

I found about the same thing comparing Maya 6.5 to Maya 7.

From Maya 6.5, I could write out High Dynamic Range RGBA Float 4x32 bit .tif files, and they'd open in Shake 2.5 and work with high dynamic range.

From Maya 7, I could not get that format (or any other format of HDR image) to render that would open in Shake 2.5

If any Maya 7 users have different experiences, I'd love to hear details!

-jeremy

pixlix2
05-08-2006, 06:04 PM
hmm, this is all pretty weird.
I did some new tests on my side and had the same problems.

Two things worked as expected:
switch to 4x16bit half, render to OpenEXR and it will open in fusion5 as a true 16bit float file (no clipping)

switch to 2x32bit float, render to *.HDR, it will open as 32bit float in fusion5

SGI, TIFu, IFF - all did not work

lazzhar
05-08-2006, 06:38 PM
...

From Maya 7, I could not get that format (or any other format of HDR image) to render that would open in Shake 2.5
....

I tryed with HDRShop and it looks like it's rendering ok. I've then saved ti Float Tiff and Combustion got it correctly.

daddyo
10-30-2006, 05:40 PM
I know this is a old thread, but here are my results:


Maya 7, with MR:

iff RGB 3x16 bit short: fail... renders 8bits
u-tif RGB 3x16 bit short: renders 16 bits but once you open in shake, it returns bad frames

I had to use .exr files to get more range out of my zdepth pass. Hopefully Autodesk will fix this.

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