why my scene lack of contrast?

[cmrhm]

Not new to Vray, but haven't use it for 1 year. Now I am trying to RUN it for a project and I think I forget some important methods to use it correctly.

 

After done some testing and adjusting some settings, I found my rendering still lack of contrast. I just can't figure out what is wrong.

 

Pls see the attached for my sunlight, sunsky and the rendering settings.

 

Also I am using 3dmax9 with Vray 1.5.

 

Pls help. Thanks for the help in advance.

[Origins]

I think you have set both gamma settings to 2.2(or 1.8)

 

just make sure vray color mapping has gamma value set to 1.0 when using 3dsmax gamma & lut settings

 

hope it helps

Edited April 11, 2010 by Origins

[Tommy L]

Its a gamma issue. There are lots of different approaches to gamma corrected images, do some reading on LWF (Linear Work Flow).

You're in Chicago?

[cmrhm]

Its a gamma issue. There are lots of different approaches to gamma corrected images, do some reading on LWF (Linear Work Flow).

You're in Chicago?

 

Thank you Origins and Tommy. I am going to twist gamma issue. Also, I will study LWF and find the answers.

 

Tommy: yes! nice to get help from you Tommy.

Edited April 12, 2010 by cmrhm

[cmrhm]

Hi, Tom, origins and others:

 

I tried twisting Gamma and LUT settings on 3DMax and VRay. But I found my rendering is still bluish. Also I tried to create a new scene. The contrast is much better, but then the blueish rendering still existed.

 

Any ideas why? I never experienced this problem before when I used VRay one year ago.

 

I changed my gamma and LUT settings based on JG3D's tutorial:

http://jg3d.net/3d-tutorials/lwf-linear-work-flow-for-v-ray-the-easy-way/

 

Pls help, I am in a deadline.

Edited April 13, 2010 by cmrhm
more info.

[aaronrumple]

Try these settings - and make sure you are using the Vray frame buffer, Vray camera, and Vray sun/sky.

 

...noticed your sun settings. I'm guessing you are not using a Vray camera since you have everything dialed down so much.

Edited April 13, 2010 by aaronrumple

[tommyjj]

are you rendering in the vray render frame?

[cmrhm]

Try these settings - and make sure you are using the Vray frame buffer, Vray camera, and Vray sun/sky.

 

...noticed your sun settings. I'm guessing you are not using a Vray camera since you have everything dialed down so much.

 

You mean Vray Physical camera? is it easy to set up?

[cmrhm]

are you rendering in the vray render frame?

I tried. similar results. But I didn't try to manipulate the image on Vray render frame.

[aaronrumple]

You shouldn't have to manipulate the frame buffer window if everything is set correctly. Here's my current project with the above settings straight out of the buffer.

[aaronrumple]

You mean Vray Physical camera? is it easy to set up?

 

Yes. Just like a 3DS camera pretty much. But uses real world exposure settings.

[cmrhm]

Yes. Just like a 3DS camera pretty much. But uses real world exposure settings.

 

That is Nice rendering. I used be able to do that without PS. Don't know why can't now. May be company's IT people took care of the gamma issue at that time? Now I am doing projects at home.

 

I began to experience Vray physical camera and changed the setting almost exactly as you suggested. The results are improving. not that bluish now. I here would like to ask you some more Qs:

 

1. Are u use those gamma and color mapping setting all the same no matter which rendering you are doing?

2. should gamma on COlor mapping have same number with 3Dmax Gamma setting?

3. for physical camera used outdoor, do we normally adjust the following settings:

f-number: 11

shutter speed: 100

film speed: 100

white balance: ?

 

My scene too bright, could this be cured by white balance?

 

Thanks!

[aaronrumple]

That is Nice rendering. I used be able to do that without PS. Don't know why can't now. May be company's IT people took care of the gamma issue at that time? Now I am doing projects at home.

 

I began to experience Vray physical camera and changed the setting almost exactly as you suggested. The results are improving. not that bluish now. I here would like to ask you some more Qs:

 

1. Are u use those gamma and color mapping setting all the same no matter which rendering you are doing?

2. should gamma on COlor mapping have same number with 3Dmax Gamma setting?

3. for physical camera used outdoor, do we normally adjust the following settings:

f-number: 11

shutter speed: 100

film speed: 100

white balance: ?

 

My scene too bright, could this be cured by white balance?

 

Thanks!

 

1. Pretty much for all renderings, interior and exterior.

2. Yes, I'm using 2.2 to correspond to my monitors.

3. I keep speed and film set to 100 and adjust f-stop. Except in extreme lighting situation. This allows me to guess based on one of the many photo exposure charts on the web. (http://www.fredparker.com/ultexp1.htm) Then I'll enable the vray exposure correction and fin tune things. I'll take this + or - and then apply it to the camera. The I can turn off the exposure correction and be almost spot on.

 

White balance will vary from scene to scene. Most of the time I just use D65 and apply a warming or cooling filter in PS. There I can warm or cool just parts of an image. The white point shouldn't make any difference on exposure, just color.

 

Do remember to set the sun and sky values to 1. (And have only 1 sun)

[Origins]

That is Nice rendering. I used be able to do that without PS. Don't know why can't now. May be company's IT people took care of the gamma issue at that time? Now I am doing projects at home.

 

I began to experience Vray physical camera and changed the setting almost exactly as you suggested. The results are improving. not that bluish now. I here would like to ask you some more Qs:

 

1. Are u use those gamma and color mapping setting all the same no matter which rendering you are doing?

2. should gamma on COlor mapping have same number with 3Dmax Gamma setting?

3. for physical camera used outdoor, do we normally adjust the following settings:

f-number: 11

shutter speed: 100

film speed: 100

white balance: ?

 

My scene too bright, could this be cured by white balance?

 

Thanks!

 

dude, since your are on dead line, leave the ideals a side and try these fail safe settings untill your project ends.

 

 

chooose Ip map as primary

LCache for sec.

 

choose reinhard for color mappping , burn value= 0.3 , adjust multiplier untill you dont see an overbright picture.

 

that should keep you away from most problems...

 

you can carry on your"learn to fish instead that of eat the fish" ideals after your payment.^^

[Origins]

1. Are u use those gamma and color mapping setting all the same no matter which rendering you are doing?

 

most of the time

 

2. should gamma on COlor mapping have same number with 3Dmax Gamma setting?

no, they both add to image gamma,so choose one.

 

3. for physical camera used outdoor, do we normally adjust the following settings:

 

my pref. work around is, create a normal cam , adjust color mapping , fine tune in vray camera

 

My scene too bright, could this be cured by white balance?

 

no , it can be cured by color mapping or fnumberor shutter speed, they all do the same thing but difference starts in animation. just use fnumber as it is easier to reach (no need to scroll down) color balance is for defining the dominant color in the scene.

 

Thanks!

[cmrhm]

dude, since your are on dead line, leave the ideals a side and try these fail safe settings untill your project ends.

 

 

chooose Ip map as primary

LCache for sec.

 

choose reinhard for color mappping , burn value= 0.3 , adjust multiplier untill you dont see an overbright picture.

 

that should keep you away from most problems...

 

you can carry on your"learn to fish instead that of eat the fish" ideals after your payment.^^

Thanks, man! Here is the result based on your reinhard recommendation. You said "adjust mulitplier". do u mean the sun/sky light multiplier or the dark/light multiplier on "color mapping"?

 

anyway, I adjust multiplier on Sun's control panel and that blurish is reduced dramaticall.

 

My another file could generate very good image without blueish at all, I only change the material from vraymtl to standard. Strange.

 

BTW, is there anyway to adjust the shadow color? or this is by default?

Edited April 14, 2010 by cmrhm

[cmrhm]

1. Pretty much for all renderings, interior and exterior.

2. Yes, I'm using 2.2 to correspond to my monitors.

3. I keep speed and film set to 100 and adjust f-stop. Except in extreme lighting situation. This allows me to guess based on one of the many photo exposure charts on the web. (http://www.fredparker.com/ultexp1.htm) Then I'll enable the vray exposure correction and fin tune things. I'll take this + or - and then apply it to the camera. The I can turn off the exposure correction and be almost spot on.

 

White balance will vary from scene to scene. Most of the time I just use D65 and apply a warming or cooling filter in PS. There I can warm or cool just parts of an image. The white point shouldn't make any difference on exposure, just color.

 

Do remember to set the sun and sky values to 1. (And have only 1 sun)

 

Thanks Aaron. I will definitely give vray camera a try after this exercise.

[Tommy L]

Turn off all the geometry and just tweak the exposure until it makes a nice sky. You can then render geometry at the correct exposure and adjust your gamma to achieve correct mid-tones.