Vray Sun and Sky for Dusk/Twilight lighting

[bob-cat]

I normally use HDRI's but have noticed a couple of people using vray Sun and Sky for dusk lighting.
2 hours later and I am no closer, does anyone have any suggestions.
Is Vray sun and sky setup to replicate this time of day (night), as soon as the sun goes below the horizon things start to get weird.

Any help please.

Cheers

[Alan Iglesias]

In my basic tests (image lit with just a Vray sun-attached) just bringing the Vray sun down toward the horizon can give some very nice dusk/sunset-like effects.

>>Is Vray sun and sky setup to replicate this time of day?

Yes, in a general sense, a simple Vray sun and sky setup will give very nice low-light (magic hour) effects just by lowering the sun towards the horizon. But given the physical nature of the renderer and Vray lighting, there are lots of things that can complicate the situation in a more complex scene.

What exactly are you seeing that is weird?

-Alan

[bob-cat]

The whole sky was turning yellow.
Ok, had another go and for it to work reasonably I had to:

1. I have set it up with a real sunlight system now @ 7pm (which is perfect real-world atm). I was pulling the sun way to far below horizon.
2. Change the white balance of the camera (around 4000k)
3. Further adjust "indirect horiz illum" for the sun, the white balance and the gamma (back to 1.0 (from 2.2 linear).

I think also I was looking at photos of sunsets etc. with alot of clouds and atmospherics which affects the colour as well.

[svetlozar.draganov]

Hello there,

It would be better if you post an example image of the exact effect that you want to achieve.
There are many variations of dusk lighting depending on geographic location , the weater and etc - sometimes the sky is yellow , sometimes purple or very dark blue.
Here is one example with typical yellowish atmosphere:

disk_lighting.zip

[Morne]

I'm not sure what he's after, but what I'm usually after is the blue-ish light in most of these images:
http://www.google.co.za/search?hl=en&q=after+sunset+blue&bav=on.2,or.r_gc. r_pw.r_qf.&bvm=bv.41248874,d.d2k&biw=1600&bih=796& um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=JRv9UPn7DIWH0A XdzIDgDA&sout=0&ved=0CCIQxxQ

When the sun goes below horizon. Just cant seem to get this effect with vraysun/sky as it's mostly the orangy sky and then totally goes wack the further below 0 in Z axis you go

[alexyork]

Don't bother using a sun/daylight system for anything later than Golden Hour. You'll never get the desired tones and feeling you're after. Same in MR. Better to stick with HDRI or use custom regular lights. You'll need to expose for your interiors and get a nice white balance between the cool blue/pink tones outside and the warm/tungsten tones inside. You'll get far more flexibility doing it this way. The daylight system is really very good right up until this point where it would be very nice to be able to totally change the sun colour manually, so we could animate the full 24 hour cycle. But this isn't possible. Best to go manual.

[Alan Iglesias]

Don't bother using a sun/daylight system for anything later than Golden Hour...

Ah, interesting, I've never tried to get that "blue after sunset" effect.

Yeah, something manual like a very dark blue/purple skydome witrh some adjusted GI attributes may do the trick...

Thanks,

-Alan

[Morne]

...totally change the sun colour manually, so we could animate the full 24 hour cycle. But this isn't possible. Best to go manual.

Yes I know how to cheat it, but this is the point, it would be nice if it could be done with vraysun/sky