Linear Workflow as in 3dsmax

[varx3d]

Hello there,

I'm struggling to find an answer to the below multi-part question, ran many tests to see the differences but still didn't conclude to the perfect answer and I think the developers could give me a precise answer.

I'm facing problems with the units scale issue in Maya compared with 3dsmax. I know that both applications calculate differently units, no matter what you set it up with mm or cm, so there are differences in raytracing calculations depending on the scale of the models/lights in the scene.

The second part of this question is what linear workflow/affect swatches/enable input bitmap gamma attribute do actually in Maya compared with 3dsmax's ones,because I've rendered all possible combinations (Linear Workflow On/Off - Affect Swatches On/Off - Disabled "Enable Input Bitmap Gamma"/ Enabled with all 3 possible choices) in Maya and still couldn't match what it was going into 3dsmax and many of combinations looked similar.

What happens with the color selector (as it is affected in 3dsmax) and the Maya 2011 Color profiles?
Are they affecting/affected by anything or so far they are not taken into account by V-Ray itself?

I want to achieve this setup as is in 3dsmax, and have the exact effect in Maya:
3dsmax units are in mm.

What corresponding units and settings need to be set in Maya to match 1:1 with the setup in 3dsmax?

Thank you in advance.

[varx3d]

Because there is no reply to confirm the accuracy of the assumption,I just assume that having mm in Maya is the same as mm in 3dsmax, in terms of V-Ray calculations.

For all the rest I just wanted a confirmation that in both V-Ray versions work the same, explanation of their functionality can be found in the documentation.

[jstrob]

I found those 2 pages talking about LWF in maya 2010 and mental ray. But I would like to see how to do it with maya 2011 and vray. One of my client is usaing vray and maya and I'm trying to help hime setup his workflow like my workflow in max and vray.

http://averpil.com/fredrik/articles/...r_workflow_pt2
http://www.djx.com.au/blog/2010/03/0...-in-two-steps/

Has anyone here found a perfect linear workflow in maya 2011 with vray?

[jstrob]

Eureka. I think i found my workflow:
In vray commmon, if using maya render view, check "enable input bitmap gamma". and the render view will apply the temporary 2.2 gamma. For bitmap file, in the "file" node, just add a vray attribute for bitmap input gamma. The rest is pretty easy.

[Metzger]

I don't know how max does it, but I can tell you that it helps to not confuse things with non-linearized textures. I use exr's written out from Mari, but Mari bakes an SRGB gamma into 16bit exr's. So I pull all textures into Nuke and then read the SRGB exr's and write them as linear exr's. Then batch convert them to tiled mipmap exrs.



If you plan on using the Maya framebuffer you want to make sure you have convert image to srgb for Renderview selected. If you are using the Vrayframe buffer, you will want the SRGB button turned on by default.

Vlado, why aren't the Vray globals defaulted for linear rendering? I think most people can get a bad taste in their mouth. From not setting things up or being aware of the linear workflow settings in Vray. You can spend a gamma hell vacation with way too much time trying to get rid of noise. It can lead to longer times in Vray than what's actually needed.

[jasonhuang1115]

I don't know how max does it, but I can tell you that it helps to not confuse things with non-linearized textures. I use exr's written out from Mari, but Mari bakes an SRGB gamma into 16bit exr's. So I pull all textures into Nuke and then read the SRGB exr's and write them as linear exr's. Then batch convert them to tiled mipmap exrs.

Hi, Metzger,
What is the difference or benifits of batch-converting sRGB exr to linear exr in Nuke, instead of setting 2.2 bitmap gamma inside of Maya on a per map basis? Is it simply a workflow concern where you can deal with all textures at once and directly use the tiled linear exrs in Maya, or there is something else?

[varx3d]

Hi there guys,

as far I can see there is plenty of confusion about proper lwf in Maya 2011 + VRay, even if the subject is pretty straight forward to understand how and why it works that way, things get a bit confusing when dealing with multiple solutions and opinions how it should be implemented across so many applications and versions.

In my understanding, you need to de-gamma all textures (99% are in sRGB color space) that you get from most sources (as with Gamma 2.2 in 3dsmax input bitmap dialog in the screenshot I attached in the 1st post) and then work linearly the entire pipeline, save the output images in linear/Gamma=1 color space and convert to sRGB during compositing for the final rendered output (still images or video).

The linear workflow button in VRay render settings tab for me it seems that has no effect, even if I read in the documentation that it helps to de-gamma old scenes that haven't been set up with proper lwf.In the past it was essential to use the gamma node in Hypershade with 0.454 values in RGB and de-gamma all the input connections of image with baked in sRGB color space and this option would save you time and effort of doing so for every shader in the scene.

The affect swatches button, only affects the maya swatches depending of the type of color mapping it has been chosen and it is not the same as it happens in 3dsmax settings dialog above, where both swatches and color pickers are affected with gamma=2.2 and you can see the effect in the entire pipeline and you don't work "blindly" as you do in Maya.

Maybe I'm somewhere wrong in all the above I've described, but that's what sinked into my mind after many tests trying to find the "golden" convertion to match 1:1 with 3dsmax lwf as occurs with the settings in the screenshot.

Strob-
There a new script that will save you from a lot of manual labor for your lwf, instead of applying it manually one-by-one to every texture node.You need to disable it of course wherever you don't need (displacement/normal maps)

http://www.creativecrash.com/maya/do...mma-correction

Metzger-
I understand fully what you do to have a proper lwf with Mary and Nuke, but for me everything becomes awkward and strange once again, after seeing that you use Gamma=2.2 in the linear multiply color mapping.Don't affect colors makes sense for proper lwf,but why do you bake into the image output the sRGB color space, instead of leaving it 1 and using the sRGB button in VFB to preview your result, or instead (if you use Maya's Frame Buffer) the option "Convert image to sRGB for RenderView" and lastly during composition in Nuke you apply the sRGB as most people recommend?

The release of the above script, which happened couple of weeks ago, made me realize once again that something I haven't understood properly and keeps this confusion in my mind about lwf in Maya 2011 and VRay.

Thanks for the feedback guys

[Metzger]

Hi, Metzger,
What is the difference or benifits of batch-converting sRGB exr to linear exr in Nuke, instead of setting 2.2 bitmap gamma inside of Maya on a per map basis? Is it simply a workflow concern where you can deal with all textures at once and directly use the tiled linear exrs in Maya, or there is something else?

Because EXR's should always be linear. 1 standard to rule them all. That's what I say. If you are using non exr's then keep them SRGB. The only Gamma you ever want is on your viewer.

[Metzger]

I understand fully what you do to have a proper lwf with Mary and Nuke, but for me everything becomes awkward and strange once again, after seeing that you use Gamma=2.2 in the linear multiply color mapping.Don't affect colors makes sense for proper lwf,but why do you bake into the image output the sRGB color space, instead of leaving it 1 and using the sRGB button in VFB to preview your result, or instead (if you use Maya's Frame Buffer) the option "Convert image to sRGB for RenderView" and lastly during composition in Nuke you apply the sRGB as most people recommend?

Correct me if I am wrong, but setting the Gamma to 2.2 in render globals says to Vray, "Hey!! We are going to view this render with an SRGB viewer lut, so focus the sampling knowing that's where the noise will be." If you leave it at 1, you will have longer rendertimes.

[varx3d]

Correct me if I am wrong, but setting the Gamma to 2.2 in render globals says to Vray, "Hey!! We are going to view this render with an SRGB viewer lut, so focus the sampling knowing that's where the noise will be." If you leave it at 1, you will have longer rendertimes.

You're completely right, forgot to take into account this major part of the equation.

Thanks for clarifying this out