Getting a white environment with Physical Sky

[Robin3D]

I'm working on a scene in Mental Ray which has to have a completely white environment. I'm using a daylight system as light source, so it automatically put a physical sky in the environment map. Though when i delete the physical sky and just turn the color white, it turns out black anyway.

 

Is there any quick way to get the whole environment white?

Edited February 16, 2009 by Robin3D

[Dave Buckley]

just a quick question as to why you are using the daylight system??? is it an exterior shot??? there are quite a few was to do it, photoshop is probably the easiest. Do the render as you have described. Then when you save it, make sure you save as a file format that contains alpha information. (i personally use .TIF) Then in photoshop you will be able to use the Max environment as a mask, in which case you can use the mask as a selection tool and then delete/replace the back environment with a new colour or just delete it

[Dave Buckley]

here is another method too, probably the scientific answer

 

the reason the environment is staying black is because of the physical unit scale being used. in your exposure control try changing it from 'physical units' to 'unitless' and then change the value for unitless to somewhere between 80000 - 90000

 

and re render. voila. i won't go into to much detail about why this is the case, but it is a quick answer just like you asked for, and also because i can't remeber the scientific answer

[Dave Buckley]

and just to prove it does work, i have just tried it

 

exposure settings for this are default mr photographic exposure (exterior daylight preset) the only changes i have made are to enable unitless and change the value to 80000 and then i also knocked the EV value down to 14 (personal preference) but a word of warning if you left the EV value on 15 and then put the unitless value on 80000 it wouldn't be white, you would need to increase the UNITLESS value

 

hope this helps

[Dave Buckley]

oops forgot to save the jpeg with correct gamma settings, but trust me, this image was grey and pristine white in the frame buffer before i exported it

[Robin3D]

here is another method too, probably the scientific answer

 

the reason the environment is staying black is because of the physical unit scale being used. in your exposure control try changing it from 'physical units' to 'unitless' and then change the value for unitless to somewhere between 80000 - 90000

 

and re render. voila. i won't go into to much detail about why this is the case, but it is a quick answer just like you asked for, and also because i can't remeber the scientific answer

I feel like an idiot not knowing this. Problem solved. Thanks a lot!