Sky problems in Vray

[dogragurjeet]

I have been trying to get good sky with the default Vray Sky as shown in most of the tuts. But after many many tries i just cant figure out how.

A> If i leave the affect background unchecked in color mapping then the sky turns white at the levels that i find the overall lighting ok.

B> If i check the same the sky gets too dull as seen in the pic.

C> I wanted to substitute the sky with a map that i have in max only. I mean i can do it in post in PS pretty easily but then I cant get the overall lighting to match the map properly. Moreover if i put the sky in the env. tab then the light coming from Vray Sky is all lost and i have to substitute with env light in Vray.

GRRRRRRR.... too many options are confusing . Please suggest as to how to best approach the problem.

Thanks in advance

[danb4026]

I have been trying to get good sky with the default Vray Sky as shown in most of the tuts. But after many many tries i just cant figure out how.

A> If i leave the affect background unchecked in color mapping then the sky turns white at the levels that i find the overall lighting ok.

B> If i check the same the sky gets too dull as seen in the pic.

C> I wanted to substitute the sky with a map that i have in max only. I mean i can do it in post in PS pretty easily but then I cant get the overall lighting to match the map properly. Moreover if i put the sky in the env. tab then the light coming from Vray Sky is all lost and i have to substitute with env light in Vray.

GRRRRRRR.... too many options are confusing . Please suggest as to how to best approach the problem.

Thanks in advance

 

There are so many different ways to do skies, it is a matter of personal preference and really depends on the specific situation.

 

But firstly, I believe the "affect background" option should have the opposite effect than you are experiencing. "Checked" is more likely to make your background "white" (too bright) if you are brightening your image with color mapping. Personally, I never check "affect background".

 

Nonetheless....have you ever used IBL (image based lighting)? This is a good way to have the "light" of the sky directly effect the overall lighting of the scene. One way to do this with Vray is to get an HDR sky image (you can download online) and place it in the texture slot of the VrayDome Light. The dome light itself acts as if it was a lit hemisphere, encompassing the entire scene. By placing the sky image in the texture slot, that image essentially becomes a lit sky giving off light. The brighter parts of the sky give off more light, the blue parts give off blue, the reds give off red. You get the point.

 

There are actually good examples of this here: http://www.spot3d.com/vray/help/150R1/examples_lights.htm#ex5

[dogragurjeet]

thank you so much daniel...... Actually have tried IBL before and it looks awesome.. the only prob is that the larger the scene gets the more computing time it requires. Until my new system arrives I think i might have to settle in for a sky dome only .

I was just noticing what you have said. It seems that i might be getting the camera f number incorrect to compensate for the bright sun and sky. I do this to avoid darkening the texture maps to get a correct feel of color. I dunno if that is correct.

I use "Reinhardt" color mapping but do not tamper with the dark or bright multiplies. Just that i put the gamma to 2.2. Trying to follow linear workflow method suggested by a tut somewhere.

Should i tinker with the dark and bright multipliers and then maybe see how it turns up?

Thanks for the link and the hints......

[dogragurjeet]

can you also point out a free sky hdri map if you happen to know please

[danb4026]

try this:http://www.hyperfocaldesign.com/free-hdri

[dogragurjeet]

thanks again

[danb4026]

I use a 2.2 linear workflow. In keeping with that, I also use linear color mapping with a 2.2 gamma and leave my bright and dark multipliers at 1. I use the camera settings for overall exposure and will fine tune light and dark in post.

 

I have never really had an issue with IBL using too many resources, but I have 12GB ram. I also don't rely on IBL for ALL of the exterior lighting. Usually I will have a vray sun, direct light etc. to add dimension and shadowing as well.

[dogragurjeet]

hmmm an i all i have is 1 gb ram he he . I just tried this tut (http://www.cgarena.com/freestuff/tutorials/max/hdri-vray/index.html) and came up with this updated sample..... is it better than last one?. please advice