Need some help with LWF settings

[loafer87gt]

Hi guys,

I am attmepting to try out the LWF process for an interior rendering I am working on. I am having some problems figuring everything out as most of the posts in the Tips and Tricks section dealing with the topic are using the older build with different color mapping settings.

So far, I have calibrated my LCD monitor, and enabled 2.2 gamme / LUT in my Max preferences. I have also checke the 2.2 input and output settings in the max gamma preferences. Under my max color mapping settings, I have it set to gamma correction with 1 multiplier, 1 inverse gamma, and 1 gamma - the deafult settings. The problem I am having is while I am having much more light in my scene with fewer lights, I am now having a heck of a time controlling the color of bitmapped materials.

Should I be using a color correction plugin to adjust the gamma or output of my textures? Is there something else I am doing wrong?

Right now, my black and white test renders using a 160 / 160 / 160 mid grey material looked great and the lighting was bang on, but as soon as I started adding in bitmapped materials things have become quite confusing.

Can anyone give me any advice or tell me if I am doing something wrong?

[Shimakaze]

First, you shouldn't (usually) have the output in the Max gamma/LUT settings set to 2.2. Leave that part to Vray.

By the sound of it you're using color without doing anything extra with the mid gray material? The problem is that the "input gamma" setting only works for inputs-- Textures. To use normal colors you should use the Vraycolor map and gamma correct that. In the final build you can use gamma correction directly, but in older builds the easiest way is to just change the multiplier to .4545.
If you don't do that then all your textures would look much darker then your straight colored materials.
To test it, try making a picture filled with the gray color you want to use and try setting that as your texture and compare it to using the straight color material.

[loafer87gt]

Thanks for your reply Shimakaze.

I was hoping you could clear up a few other things for me.

You said that I don't need to set the Gamma in Max to 2.2 . Does this mean that in its place I set my color mapping in my Vray rendering settings to gamma corrected and enter 2.2 for the gamma number? Also, should I leave the 2.2 input and output set in the Max gamma settings?

In regards to the Vray color settings, I gather this gamma corrects plain untexture finishes - say for example if you are trying to match a particular paint finish from a manufacturers website. Is this correct? Is there a similar way to get properly gamma corrected textured materials or does setting the 2.2 texture input automatically do this for you?

I guess what's really frustrating me is that with the current way I am working the materials in the editor look nothing like the rendered ones.

[Shimakaze]

You don't need to set the "output" in the max gamma settings.

Here's a picture:

If you calibrated your monitor to sRGB space (gamma 2.2) then you should set it up like in the first dialog.
Next, turn on VRay's built in frame buffer. If you don't do anything it will show the picture exactly the way it will be saved (max's frame buffer won't).
Any picture you render will be linear. You can preview what it would look like once gamma corrected by clicking on the sRGB button in the VRay frame buffer but this is ONLY for previewing. It will not affect any pictures you save. if you want the pictures you save to be in sRGB space (if you're gonna upload them directly to the net for instance) then you should do like in the second part of the picture and set the vray gamma correction to 2.2. doing that has the same effect on the image as clicking the sRGB button except it does affect the saved picture. Just make sure you don't do both at the same time.

The input option in the Max gamma/LUT settings gamma corrects any images you import into max. Meaning all textures. the reason you should use the VRayColor map is because normal color swatches aren't affected by that setting.

[loafer87gt]

Thank you very much for taking the time to help me out Shimakaze. It is much appreciated!

Have a great weekend!