linear workflow in V-ray for Maya - still confused!

[Richard7666]

Interesting. Though with greyscale values such as what would be used for a height map of any kind, you're basically eyeballing it anyway. Though it would affect contrast between reflective and non reflective areas (reflection map), or high and low areas (bump map) etc. Come to think of it even an 8bit displacement map would be affected. I guess the reason people use 32bit displacement maps so often is to avoid this hassle?
And that they DO indeed use 32bit maps also implies that yes, 8bit displacement does need to be corrected?

[Dariusz Makowski (Dadal)]

The 8 bit displacement has a range of 0-255. So in simple terms if u have 1 cm high displacement the range of 128 will be around 0.5cm. So basically you have very short range. U will see stepping and other issues. As to 32 bit u have range 0-66000+ or so(I cant remember exact number) So at the end you have a lot more steps/control there for displacement looks better and has more depth do it. U cant really see by eye the depth unless u view different exposures but its there.

As to grayscale maps as long as they are not 32 bit they need Gamma correction on them.

[varx3d]

Hello there,

It seems that you've been in the same hell as I've for months trying to decompose the mystery through the 1:1 conversion of 3dsmax's VRay workflow to Maya, which may share the same render engine but Maya has some areas that left undiscovered.
This happens due to the fact that 3dsmax has a great few-clicks-to-setup linear workflow adaption, compared to the hardcore Maya.

Since I was a former 3dsmax Arch-Viz user and was trying to stick with the pipeline that everybody is still using for photorealistic results, some things stabbed me along my path to switch to Maya's logic,which is technically more hardcore and you need to take everything into consideration compared to the user-friendly 3dsmax that hides many things in order not to trouble you how to -technically- do them.

Forget about Gamma nodes or Texture input attributes entirely, I've tried them all and their combinations.
The linear workflow does it trick,because it applies an inverse gamma to color swatches and texture files without the need to to it manually...or at least that's what I did find as the best solution,only the programmers of VRay core in both platforms can tell If it's spot on or I'm entirelly off the truth.



By trial & error the result you are looking is this.In order to have pure and unaffected swatch from the color mapping you need to have Linear (as in 3dsmax) and switch it before render to Exponential or anything else you might prefer.
Ideally, if I knew how to code in mel, you could attach a pre-render mel script to change the color mapping to another of the default linear, to see the render in different color mapping mode.

That's all,I hope it helps

[bazuka]

u have a mistake there amigo, Linear Workflow should be OFF, thats a fake linear workflow (check the vray manual )

- Note that this option is intended to be used only for quickly converting old scenes which are not set up with proper linear workflow in mind. This option is not a replacement for proper linear workflow.

[varx3d]

Yes,in your pure meaning of proper LWF for VFX it's incorrect (You need to activate the Don't Affect Colors as well)

I'm speaking about this setup I was trying to achieve 1:1 from 3dsmax to Maya for Arch Viz tutorials conversion


The VRay manual doesn't clarify anything,in contrast it confuses you without explaining what happens under the hood when you use this button.
The 3dsmax users never use it since they have the solution in the Preferences,in Maya you need to do it this way in my opinion.

[Dariusz Makowski (Dadal)]

varx3d you are doing it wrong. U putting a 2x gamma correction on ur image using that 2.2 gamma and no gamma correction on ur textures. U have to correct ur textures and get a EXR as output for proper linear workflow.

[varx3d]

Yes,for proper LWF you're speaking I'm wrong, I know it!

I'm speaking about using the same setup in Maya as the Arch Viz people to get the great renders you know.
I'm speaking ONLY about 3dsmax preference settings transfered correctly to Maya.

Don't forget that you speak about VFX production,the ArchViz guys DON'T care about proper LWF, only about the resulted rendered image!

Sorry for the confusion guys

[Richard7666]

By contrast, I've actually got a good 'proper' workflow running now:

(I will double check my settings and post them later)

The only thing that is a bit annoying is the colour picker colours. It's easy peasy for textures, just add the Texture Input Gamma attribute. Whereas with solid colours, I still haven't figured out how to get everything looking the same between the viewport, the preview swatches, and the colours displayed in the colour picker itself, and the final render (see my earlier posts where I try to get the copper roof colours all looking right)

[Dariusz Makowski (Dadal)]

Yes,for proper LWF you're speaking I'm wrong, I know it!

I'm speaking about using the same setup in Maya as the Arch Viz people to get the great renders you know.
I'm speaking ONLY about 3dsmax preference settings transfered correctly to Maya.

Don't forget that you speak about VFX production,the ArchViz guys DON'T care about proper LWF, only about the resulted rendered image!

Sorry for the confusion guys

Aaaaaaaaaaa right that makes total sense ! I was reading this forum from a while and just scratching my head with the things people say about LWF and how badly off they are of the actual subject hehe

Thanks for info !

[bazuka]

amigo looks nice, ur missing some bump/disp on stones (corner of the house), small bump on wood (house)

maybe some nicer clouds and should be it

here is a quick test i did for grass (yeti), most of the things r default... (http://www.chaosgroup.com/forums/vbu...492#post569492)

cheers

By contrast, I've actually got a good 'proper' workflow running now:

(I will double check my settings and post them later)

The only thing that is a bit annoying is the colour picker colours. It's easy peasy for textures, just add the Texture Input Gamma attribute. Whereas with solid colours, I still haven't figured out how to get everything looking the same between the viewport, the preview swatches, and the colours displayed in the colour picker itself, and the final render (see my earlier posts where I try to get the copper roof colours all looking right)

[Richard7666]

Haha yes I hadn't gotten round to setting up my displacement yet.

The house just happened to be a good scene to try various LWF setups with.

[varx3d]

Richard, could you please post some pics/settings for the final setup you've used to reach at this result?

[Richard7666]

Will do, super busy this week but so won't be for a week or so and if I haven't by then pm me a reminder.

Basically though it's just the colour mapping settings I posted on the last page, and every texture has the Vray Texture Input Gamma attribute applied (leave it at default 2.2).
Vray Sun&Sky, physical camera at default values (good for daytime usually) with maybe a bit of white balancing depending on what your sun doing. I think I'd have hit the sRGB button (or applied a curve) on the vfb too because of Don't Affect Colors enabled.
Under the Settings vray render global tab, in the 'post production' area, I also put to put Saturation at about 0.4 from memory so that the sky didn't make everything too blue.

I forget what I did for my solid colours such as the copper roof, I'll have to look into it again.

[Dariusz Makowski (Dadal)]

Heya

Regarding LWF I have an correction to my early statement. We were doing some tests at work yesterday with colleagues at work and it turns out if you are using 8/16 bit files and use their Use alpha as luminance thick or standard node luminance to control glossiness etc then YOU DO NOT CORRECT THAT. It appears that 8/16 bit files alpha/luminance channel stay linear so there is no need for gamma node.