So what's the deal with night skies?

[agentunawares]

Ever since I started running polls on my Patreon page to see what kind of skydomes people are interested in, I noticed an interesting trend. If one of the options falls in the sunset to sunrise timeframe, it gets picked every single time. I thought this might be due to the low number of voters but I accidentally opened one to the public for a day or two and again the night theme was overwhelmingly chosen.

So what's this about? Is there a dearth of available lighting for late in the day? Is everyone out there dying to render under moonlight and nobody makes this possible?

 

[tparo]

I tend to find that there are fewer night time skies (HDRIs) available than any other, especially good ones. I do have a few now and some sunset ones. Daytime sunny skies are numerous personally I'd love some dark stormy skies. Night lighting is difficult though so a good HDRI really helps.

 

[Rae134]

I just gave my opinion on your FB question

 

[phdubrov]

Not aware of any good moonlight HDRIs. Want one... or half a dozen.
There are some good city nights out here, and a few outdoors.
And I think people always choose dawn/dusk before noon, simply for dramatic. Good storm/rainbow/godrays... probably not. But it's even more hard to do than moonlight I think.

 

[tparo]

Not aware of any good moonlight HDRIs. Want one... or half a dozen.
There are some good city nights out here, and a few outdoors.
And I think people always choose dawn/dusk before noon, simply for dramatic. Good storm/rainbow/godrays... probably not. But it's even more hard to do than moonlight I think.

I have some good night HDRIs that are by Dimension Theory over at Daz.

 

[phdubrov]

Not just night. I'm talking exactly about moonlight with the visible moon.

 

[Rae134]

Not aware of any good moonlight HDRIs. Want one... or half a dozen.
There are some good city nights out here, and a few outdoors.
And I think people always choose dawn/dusk before noon, simply for dramatic. Good storm/rainbow/godrays... probably not. But it's even more hard to do than moonlight I think.

I think a rainbow one would be neat I don't know if godrays would work, would be hard to position the thing you would like in the midst of the godray

 

[agentunawares]

This is fascinating. I had no idea there was such interest in this.

 

[Rae134]

well speaking just for me, I have a crappy computer so I can't have much in a scene otherwise it won't render at all (which is why my images are quite simple) so having good quality HDRi's saves me from having to fill my backgrounds so I can put more focal points like animals or charters in.

So any kind of good quality HDRi's are very much welcomed by me. (For me personally, I'd love some good horse paddocks/fields hint hint LOL)

 

[Bonnie2001]

I never really gave it much thought, but now it's come up I do prefer the softer light of any HDRI's that are not noon to afternoon sunlight.

 

[agentunawares]

Well this is enlightening. My first set of night sky maps I hacked together from "normal" renders and photo references which resulted in a lot of limitations on what I could do (it was basically impossible to get moon phases). Now that I know people are so interested in this I'll take the time to build a procedural starmap and render the moon as an actual object which should allow for a whole lot more options.

 

[seachnasaigh]

I have some spherical panorama sky HDRIs, but the file size is large so it's awkward to make a package with them. I usually use Poser's math nodes to exaggerate the brightness range of a regular JPG.

For those interested, I have Godray skies (with soft-edged Godray props for use in the foreground) and a few rainbow skies. Several night skies are in my packs. Neither of these packs are HDRI, but you might find them useful.

sky pack 1

sky pack 2

 

[Bonnie2001]

Go raibh maith agat for those seachnasaigh, I will register at ShareCG and download them after school.

 

[tparo]

Not just night. I'm talking exactly about moonlight with the visible moon.

The night one by DT I have do have the moon visible.

 

[Ken1171]

Personally, I think I can handle outdoors daylight rather easily with or without HDRI, but night lighting is way more complicated to get right. When it comes to real world photography, dusk and dawn times tend to provide the BEST lighting to shoot people and places. It provides the best shadows and a more dramatic lighting. That's my 2 cents on the subject.

 

[Dakorillon (IMArts)]

I have some spherical panorama sky HDRIs, but the file size is large so it's awkward to make a package with them. I usually use Poser's math nodes to exaggerate the brightness range of a regular JPG.

For those interested, I have Godray skies (with soft-edged Godray props for use in the foreground) and a few rainbow skies. Several night skies are in my packs. Neither of these packs are HDRI, but you might find them useful.View attachment 35085

sky pack 1

sky pack 2

I have a question. I've been reading and studying for months now, and I can't really find a definitive answer. What makes HDRI images HDRI? I know they are created by bracketting shots, so that the darks aren't too dark, and the highlights aren't blown out, But, What other info is there that makes them HDRI? Can't you just use any image in the Enviro Tab and the same one in the IRay enviro spot and get the same effect if the image has good lights and darks? What else am I missing? I just don't get what makes HDRI different from HDR, or a normal image for that matter, other than the aforementioned light/dark bracketting? And the fact that somehow it glows on its own...But you can make lots of things emit light...so?

 

[phdubrov]

Nothing special.
Just 16 or 32 bit per channel.
HDR Illumination - just an HDR Image on a spherical emitter around a scene. The sphere could be "virtual" - i.e. not visible in the scene as an object (Iray or Poser Background node) or visible - there are a lot of domes/spheres both for Poser and DS.
the darks aren't too dark, and the highlights aren't blown out - it is not a goal of bracketing, it's the result of a tonemapping of an HDR image.
HDR vs LDR - with LDR image you could have problems (banding) if you want to change exposition or in postwork.

 

[Ken1171]

What makes HDRI images HDRI?

The quick and simple answer to that is color depth. In addition to shooting in RAW mode with multiple exposures, HDRI is stored with a much wider color depth. This is what gives it a the "high dynamic color range" that is implied in the name. By shooting multiple exposures, you fill in the color range values for each frequency interval, creating a more complete color spectrum that represent the real world image.

The human eye can only perceive a rather narrow band of the light spectrum, but within this range, the color depth basically infinite. We cannot store infinite values on a computer, but we can make it as wide as possible. This is achieved with a wider bit representation of the data, which provides more accurate results. It's a all about color depth. Since its values are exponential, an increase from 8 to 16 or 32 bits is a HUGE gain in color depth representation. Add multiple exposure samplings to this, and you have HDRI.

 

[Dakorillon (IMArts)]

Nothing special.
Just 16 or 32 bit per channel.
HDR Illumination - just an HDR Image on a spherical emitter around a scene. The sphere could be "virtual" - i.e. not visible in the scene as an object (Iray or Poser Background node) or visible - there are a lot of domes/spheres both for Poser and DS.
<snip>
HDR vs LDR - with LDR image you could have problems (banding) if you want to change exposition or in postwork.

Okay, so to be HDR-I it has to be Spherical, AND it has to be ready for, or ON a dome/sphere with emission. Right?

 

[Dakorillon (IMArts)]

The quick and simple answer to that is color depth. In addition to shooting in RAW mode with multiple exposures, HDRI is stored with a much wider color depth. This is what gives it a the "high dynamic color range" that is implied in the name. By shooting multiple exposures, you fill in the color range values for each frequency interval, creating a more complete color spectrum that represent the real world image.

The human eye can only perceive a rather narrow band of the light spectrum, but within this range, the color depth basically infinite. We cannot store infinite values on a computer, but we can make it as wide as possible. This is achieved with a wider bit representation of the data, which provides more accurate results. It's a all about color depth. Since its values are exponential, an increase from 8 to 16 or 32 bits is a HUGE gain in color depth representation. Add multiple exposure samplings to this, and you have HDRI.

So, if I created a picture with 16 or 32-bit depth and saved it with that information (.tga? .jgp? .tiff?) , then, even though it wasn't a photo, it would still be HDR? Basically, can anything other than photos be HDR?

I'm not a photographer, and my last class was in High School, and I only did so-so in it, So I know bits and pieces, but have lots of gaps in knowledge. Thank you for your patience in answering, both you and phdubrov.