vray sun and sky with direct and dome

[mikegentile]

hi everyone
i have a theory that i wanted to throw out there. i have two images.
one made with vray sun sky and exposure. the other simply the vray dome with a direct light using vray area shadows
i know the vray sun sky system controls the color and intensity of the light based on the angle of the sun, turbidity and ozone.

from a purely image stand point, is it possible to duplicate the image produced with the sun sky system with only a dome and direct light? is there something visually that the vray sun sky system can do that the direct light and dome cannot?

also does the area shadows size of the direct light match up with the disc size of the vray sun?

thanks in advance

mike g
focus 360

[^Lele^]

In principle, no, there isn't anything you couldn't do with a gradient BG (mapped to a dome light if preferred) and a direct light.
The only trick i may suggest is to use a nice white plane to colorpick the sun values precisely, so to nail the float intensity correctly (it's MANY times above the standard 1.0 multiplier of a direct light).
The principles of this are in that old tutorial of mine on sun, sky and physcam in the tips and tricks section.

[mikegentile]

thanks.
i'll check that out.

[Aldaryn]

Also, you might want to check out This link. Here you will find a quite good hdr dataset from the daytime sky what you can use to measure intensities, or to map the dome light directly with it. Results in terms of light intensity and distribution are quite similar to Vray sun+sky system, color saturations however are not.

Best regards,

A.

[Da_elf]

one major thing i can think of though is that without sun/sky/exposure it would be kinda like using a LDR image for reflections as opposed to an HDR

[^Lele^]

That's what i meant by using a white plane to mimic the sun intensities: with a proper color and multiplier (or a vray color map as projection map for the light) the exact same values as those of the sun can be achieved.
Hence, the same exposure through the Physcam.

[Da_elf]

plus trhe sky would need to be made up of a gradient ramp with output maps to increase the intensity. then once the sun and sky have been recreated to match an HDR things will be bright and you will need to use exposure to bring it back down. which is where he doesnt want to be