merging daylight and artificial light

[mtawheed]

I want to create a realistic merge of daylight and artificial light, I simply don't know whether to use logarithmic exposure control or automatic exposure control and what other settings you would recommend

 

thanks

[theqball]

Not really a suggestion on which to use, just thought I would share a few things that I have learned about these…

Logarithmic does more of a bandpass filter, clamping the whites and darks more severely than the mid-ranges. This is actually closer to what the human eye does. (we rarely see pure white or pure black in real life)

Automatic is a linear filter that is calculated based on what light the camera in your scene is being subjected to. It can be easier to setup in some cases, but can also cause problems if the Camera is animated.

Linear is the same as above it’s just not auto calculated every frame and has to be manually dialed in.

All of these can be further adjusted with the brightness and contrast settings. I tend to like logarithmic more than the others, the linear filters have that CG/Digital look to it with really bright whites and pure black areas in the shading. Either way by using exposure control you’re not changing the lighting data in your scene you’re just changing the “look” of it at render time. So, really you could play with any of them at no cost and see which one give you the results you are after.

Tips?

If you are working with an exterior daylight scene then check the “Exterior Daylight” option, this will bring your data into a closer range before you start tweaking brightness and contrast settings.

If your scene is really dark or really bright, check to make sure your scene units is properly setup and that your lights are configured to emit the proper amount of light, and then adjust the “Physical Scale” to bring it into range before adjusting anything else.

[mtawheed]

Dear Shane

Thank you very much for your reply, really appreciate it, I just have a simple inquiry, what is the physical scale? and what should be its value ?

 

thanks

[hussein]

hi all ... physical scale is for std. light only ..it will change its effect but does not have any affect on the radiosity .

[theqball]

if you do a search in the user reference for "Pseudo Color Exposure Control" and click on the one that is titled "Pseudo Color Exposure Control" it will give you a pretty good explaination.

 

a short exerpt from this page...

 

General Guidelines for Physical Scale Values

• If you use only Photometric lights, IES Sun, and IES Sky, the Physical Scale value is disregarded, and you don't need to change it.
  
• If you use Standard lights, the Physical Scale value acts as a conversion scale that the radiosity engine uses to calculate energy. Set it to the equivalent of the brightest light source in the scene. This will set the appropriate conversion scale for reflections, self-illumination, and all other non-physically based elements a Autodesk VIZ material offers.
  However, if you use the Affect Indirect Only flag in the Logarithmic Exposure Control, you don’t need to worry about the physical scale setting.