I have read so many different ways of doing this recently my head wants to explode. Also, for my diffuse texture file nodes, do I want to only add the Vray Input Gamma attribute to diffuse textures? Not even say, coloured reflection textures? What about greyscale textures?
I’ve attached a screenshot of my settings and the results I get with them (note the splotchy roof is because it’s a blend texture)
I have added a Gamma node to the diffuse colour slot for the roof material, as you can see the colour of the Gamma node (colour palette window on the right) matches the rendered result. However, the viewport and the material’s diffuse colour slot swatch show as a dark brown!
The same thing happens with the wood texture I have shown in the hypershade; the material swatch can be seen to be very dark compared to the actual texture plugged into its diffuse slot.
Note that the ‘affect swatches’ option in the Color Mapping section of the render settings has no effect on swatches unless I set the gamma in there to 2.2. However, doing that causes double gamma to be applied (as I already have the Vray Input Gamma nodes on textures and Gamma nodes on swatches) and the render becomes washed out.
If someone can tell me what’s right and what’s wrong in my setup, I’d appreciate that. *Note that I save as 16bit EXR and do a bit of post work in Photoshop but not much beyond a bit of levels correction. I’m not bringing the images into Nuke or anything fancy.
Besides, if you use file textures, remember to activate vray extra attribute “Texture input gamma” (in the maya file node) attribute editor, Attributes>Vray>TextureInputGamma. If you’re working at gamma 2.2, then leave it at 2.2
So apply the Texture Input Gamma attribute to ALL coloured textures, eg the reflection texture of the copper roof? Okay.
Did you mean to tell me to also tick “Don’t affect colors (adaptation only)” though Bazuka? Because hitting the sRGB button in the VFB makes every really washed out without using that option. It’s still washed out even without it though.
Affect Background → CHECKED
Subpixel Mapping → off by default, but check if needed
Don´t affect Colors → CHECKED
Linear Workflow → NOT CHECKED!
Furthermore activate the little sRGB Button in the vray framebuffer and for the Maya Render View go to Display and activate 32Bit floating point HDR (maya restart required)
Output-Format OpenEXR of course.
For the diffuse colors (if not pure colors) use a gamma correct node with 0.455 0.455 0.455
for diffuse texture files activate texture input gamma in attribute editor → attributes → Vray → “Texture input Gamma” leaving the values at default
We do not correct bump, reflection, refraction etc. colors + textures.
HDRs+EXR aren´t corrected either of course.
If u use a 8bit image in the background slot of the vray environment it needs correction as well.
Our compositing department so far never complained about the output files not being linear
Hope I didn´t miss anything.
Cool, this is the workflow I’ve used in the last image I posted. However, I don’t have the sRGB button enabled in the vfb; when I hit that button the result becomes very washed out (the same as it appears in the second render, the one where I didn’t hit ‘don’t affect colors’).
Should I be getting such a washed-out result when applying sRGB? It’s easy enough to correct with curves in either the VFB or Photoshop of course, but is it correct in the first place? Because I see most raw renders don’t look as washed-out as mine with sRGB applied.
Also, using a gamma node at .4545 on my diffuse colours makes them appear different between the hypershade, viewport, colour palette and the final render. See the first image I posted; that light beige/brown is what I’ve picked in the gamma correct node’s colour palette. However in the material attributes, viewport and hypershade, it shows as a rich dark brown. So it makes it very hard to judge.
EDIT:
people in this thread http://forums.cgsociety.org/showthread.php?f=87&t=1060588 such as Dave Girard say to gamma correct reflection, refraction textures too. Basically anything that affects colour. The only 8bit textures not to correct are things like bump and so on.
Start maya
Pick vray as render
Load texture apply either Utility node>gamma>0.4545/0.4545/0.4545/ or vray input gamma node 2.2 or 0.45(cant remember)
Then in vray frame buffer use SRGB
Save to openEXR
It makes sense.. Maybe I should do some changes in my own scenes. But yes, bumps, displacements, blend weights, etc.. shouldn’t be gamma corrected, but reflection/refraction color textures I don’t see why it shouldn’t. I have new doubts!, I’m gonna try it.
In Reflection Amount of a VrayMtlMaterial imagine you’ve a texture with a part at 0.2 grey (20% reflection), part with 0.6 grey (60% reflection) and part at 1.0 (100% reflection).
Vray will respect this values “reading” the map. As is. If you compensate it, you’ll loose this values, and the reflection amount control. Vray expects a range from 0 to 1 for this channel.
8 and 16 bis images by default have inbeded gamma of 2.2. As we want to work in linear (1) we have to degama all 8/16 bit images to 1. So thats why we use maya gamma node with 0.45454545 to degama the 2.2 to 1.0. We have to do it on all 8/16 bits textures. No matter what we use it for. In vray I think I was just using vray build in gamma correction cant remember haven’t used it for a while.
I remember that when you use a camera for take a photography, camera is producing an image which gamma you should correct, the same for scanners, etc.. but when you want to control the reflection amount (not the color), you use a number, usually from 0.0 to 1.0. If you want define “regions” with different amounts in your textured object, you create a texture with this different parts with differente values, not with the eye, but with a photoshop/gimp color info. I mean, the range of the image for this purpose is from 0.0 to 1.0, not a brutal hdr range. So if we talk about this “reflection texture” in HSV, I believe the V (valor) should be from 0.0 to 1.0. H and S, the truth, I don’t know…
The parameter you cant remember is in the file node texture > attributes > Vray > Texture Input Gamma.
I never hear of having to gamma correct any camera/scanner images ever. If u use 8/16 bit images and they have imbeded gamma 2.2 u HAVE to use gamma corection. Unless those images DONT have gamma imbeded. It dont matter if u use it for reflection bump normal or what ever else you have. HSV is 0-1 or 0-255. HSV = RGB in basic just different control of attributes.
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?
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.
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.
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.
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.
hehe its simple
