More sky/SU sun options

V-Ray for SketchUp V-Ray for SketchUp :: Wishlist
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I’d love to see more options for the sky setup in VRay. More and more I’m feeling that I need to be using HDRIs to achieve the effects and realism I want, but the handiness and accuracy of VfSU’s sky setup is so useful. As much as I like the logic and straight-out-of-the-boxiness of the current setup it’d be really nice to be able to choose the colour of the sun separate from the sky for example, to adjust their relative influence on the scene (or is this possible already?) and to choose those colours using pickers instead of (or rather, as well as) by adjusting turbidity and ozone.

While I’m on the subject it’s been brought up before, but not in the wishlist: it’d be great if you could blend the sky with an HDRI for even more control. I don’t recall what the explanation was for this currently not working, but it’d be very useful.

Thanks in advance,
Jackson

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Re: More sky/SU sun options

While I’m on the subject it’s been brought up before, but not in the wishlist: it’d be great if you could blend the sky with an HDRI for even more control. I don’t recall what the explanation was for this currently not working, but it’d be very useful.

You can already do this…add a blend texture and put the sky in one slot and the hdri in the other…mix to taste.

choose those colours using pickers instead of (or rather, as well as) by adjusting turbidity and ozone.

No chance…the sun is not an image, its a system (of mathematical equations) in which turbidity and ozone are input parameters for that system. The idea is that the system represents the range of values/colors that could appear in the sky. Think of it like picking the conditions rather than a color (ie…today’s kinda hazey->higher turbidity)

it’d be really nice to be able to choose the colour of the sun separate from the sky for example

This is possible, but requires that you don’t use the default light. When we add direct lights, then you will be able to do this.

to adjust their relative influence on the scene (or is this possible already?)

Again, when the sun is actually separate, they you will be able to control everything independantly…right now you could try a thing where you adjust the multiplier within the actual sky, then adjust the texture multiplier. That will allow the sun and sky to be at different intensities. I think the relationship is not necessarily 1 to 1 in terms of the sun intensity multiplier vs the texture multiplier.

Although I like the Sun and Sky, I tend to limit is usage just because its just an even gradient. Unless you’re goal is to render something when there’s not a cloud in the sky, its tends to lack a realistic result for the background or reflections. For this reason, my general exterior setup is the sun/sky for GI and an HDRI for background and reflections. This allows the lighting to be very quick, and I just do a few adjustments to the intensity of the hdri, then I’m done.

HTH

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Re: More sky/SU sun options

Hm… problems that you can’t change the HDRIs multiplier. When you close the window after selecting the HDRI and upping the multiplier to be able to match the Sun which you’re blending the multiplier is reset to 1.

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Re: More sky/SU sun options

Just realised something… Turning down the Sky and upping the Blend map multiplier works.

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Re: More sky/SU sun options

Thanks for all the answers and info Damien.

I found the thread where this was discussed here- it seems it doesn’t work with Physical Camera? I started experimenting with blending sky and HDRI a few months ago, setting an enormous multiplier for the HDRI to try to overcome the effect of the sun, but it seemed that the sky environment always overrode it.

Are you using it with Physical Camera?

I understand that it’s a system, but I just imagined there must be room for more adjustment within that system. The most common problem I’ve come across is when I’m trying to achieve a very white natural light. I know there’s no such thing as natural white light as such, but under certain cloudy, but bright conditions the light is almost white to a degree that I just can’t quite replicate using VfSU’s sun setup. Adjusting turbidity and ozone produces light that is either too blue, too yellow (or if I go really crazy with the settings too green!).

Do you mean using an omni instead of the sky environment?

Do you mean adjust the sun multiplier as well as the environment texture multiplier?

OK, I’m off to experiment again! Thanks for the info guys,
Jackson

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Re: More sky/SU sun options

Yes

No, he refers to direct light, a light type that’s not yet availible in VfSU.

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Re: More sky/SU sun options

As to the blending the sky and an hdr, I would recommend bringing the sky down to the illumination of the hdr rather than the hdr up to the intensity of the sky. Just use .03 for the Sun Intensity within the sun settings and then you shouldn’t have to worry about the texture multiplier funkiness. Then just adjust the texture multiplier of the blend and you should be good.

As for adjustment in the system, the only available inputs are the ones that we expose. In general, you won’t find any options that aren’t exposed within V-Ray (i guess this is both a blessing and a curse). Keep in mind that the Sun/Sky system is meant for ideals. IOW a perfectly sunny day with no clouds, which of course rarely happens. Does that mean its not useful? No, but understand that its just not set up for those extremely cloudy days that are more gray than anything else, or those really interesting colors in the evening sky that are because of the pollution coming from Joe’s Chemical Dump that’s down by the docks ;D

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Re: More sky/SU sun options

I got Sky + HDRI working really well, I posted my settings and render in the previous discussion so it’s easier for folks to find than this thread. Although my test was deliberately wrong (i.e. the sky and HRDI shadow contradict each other) the flexibility this allows to create very white, or very red sunset renders, but while maintaining “accurate” shadows is exactly what I was after. Thanks for the advice!

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