The story so far, my scene is set, i'm torn between terradome skydome and bb's envirosphere. I am using a moon planetoid prop and want to get a realistic moon light effect.

1. skydome or bb's sphere?

2. lighting...do i create an additional light or can i assign light values to the moon prop to simulate moon light, i dont want the whole scene looking like it is bathed in light, i want to achieve the soft/hard shadow effect of moonlight.

there is very little in the scene, character, dynamic cloth, tree in  distance and moon and ground..

any tips  gratefully accepted.........

The moon, like the sun, subtends an angle of 1/2 degree and is so far away that it might as well be infinite. In other words, use an infinite light with a .5 degree shadow blur radius.

Unless you simulate a long-exposure image (where night turns to day) the sky contributes nothing of importance to the lighting, so it doesn't matter what you use for celestial object (stars, planets, the moon) representation.

A proper (and I mean proper with 10000:1 contrast) HDR image of the sky (with moon in it) would take care of itself for sharp shadows, but I have never seen any such thing ever published. Maybe from Dosch. But most "HDR" images are nothing of the sort.

LDR images are limited to a dynamic range of 255:1. HDR can (and should) be 10000:1 with the sun or moon in them, but the most I've seen is around 1000:1. This is because photographers don't know what we need for HDR in CG. They're just doing it for reasons I don't understand.

So - add an infinite light and call it done.

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There is also the never ending debate about color. Moon light is the same color as sun light. This means slightly yellow. But perception using our night vision (rods versus cones) gives it a blue tint. Cameras also pick up the blue a bit more. Some purists argue it's not about perception, but actual color. Other purists argue it's not about actual color, but perception. Personally, a little extra blue makes it more real. Perfect? No. I am tired, though, of the endless inability of some people to grasp the not-so-subtle distinction between these two words: better, perfect.

Do what you like - not what other people like. I hope you find this info useful, if not definitive.

Using parameters palette:

Red = .8

Green = .8

Blue = 1

Intensity = .2

Using properties palette:

Ray Trace shadows

Shadow Blur Radius = 0.5

Shadow Samples = 19

Note: This is rendered with GC=2.2 in PP2012. You have have to futz property values around a lot without GC.

In addition to BB's suggestions, I usually add a black depth cue to night scenes, start distance 0, end distance determined by the background,  to add some depth and a loss of detail in the distance.

It may not be accurate, but it 'seems' to help.

Bill

thanks guys, just gonna put those to the test in my scene, i'll post soon as it renders for comments and advice.............

Quote - There is also the never ending debate about color. Moon light is the same color as sun light. This means slightly yellow. But perception using our night vision (rods versus cones) gives it a blue tint. Cameras also pick up the blue a bit more. Some purists argue it's not about perception, but actual color. Other purists argue it's not about actual color, but perception. Personally, a little extra blue makes it more real. Perfect? No. I am tired, though, of the endless inability of some people to grasp the not-so-subtle distinction between these two words: better, perfect.

Do what you like - not what other people like. I hope you find this info useful, if not definitive.

I always thought that moonlight should be at least silver-gray because the moon is gray, in other words the color of the light bouncing off it should be the same as the moon, plus a hint of blue (the AO of the night sky perhaps).

erm having problems with intensity at 0.2, rendering virtually black coz even with idl on, becuase im using a night sky enviro dome, theres no other light to bounce from anywhere, just tweaking it up a bit, will post in a min

Where you are makes a difference.  Use .2 if you are in the mat room, 20 in the pose room.

So sorry - I wrote parameters but my head is in the material room. I think of 20% as .2.

I meant 20%.

Quote - I always thought that moonlight should be at least silver-gray because the moon is gray, in other words the color of the light bouncing off it should be the same as the moon, plus a hint of blue (the AO of the night sky perhaps).

Gray means reflects equal amounts of all colors, maintaining the RGB proportions. So - yellow reflected on gray is just darker yellow.

If you shine blue light on a gray surface, it is the same blue just darker.

Shine red light on a gray surface, it is the same red, just darker.

So you said it wrong. The color of the light bouncing off it should be the same as hit it.

I am constantly amazed that people don't know the most basic premise of reflection.

If the color of arriving light is L

and the color you see on an object lit by L is S

and the color of the object itself is C

then the relationship is:

S = L * C

That means that what you See (S) is the result of multiplication (*) of the light color (L) and the object color (C).

If you see yellow (S = yellow)

and the light arriving is white (L = white)

then the color of the object must be yellow (C = yellow)

because the only way you can solve this:

yellow = white * C

is

C = yellow / white = yellow

Gray objects are objects where the RGB reflection values of its color (C) are equal.

So:

S = L * C

Break that down, assuming k is the equal RGB gray level found in C:

S = L * [k, k, k]

And break the light down into lr, lg, lb:

S = [lr, lg, lb] * [k, k, k]

The product is:

S = [lr * k, lg * k, lb * k]

I hope you can grasp the meaning of that. Suppose it is a 50% gray, so that k = .5.

Then what you see is:

S = [lr * .5, lg * .5, lb * .5]

Another way to put it is:

S = L * .5

Quite simply, a 50% gray object reflects exactly the hue and saturation that is striking it, but only half the value or intensity or brightness, whatever word you like.

Here's a picture I just took, note it's in the day and higher in the sky so that might skew things.  It looked at the RGB and its a little more blue than anything these.

Illustration on the left: Because we know that the sky adds an ambient blue color to everything, you can simply subtract the light blue sky color from the photo, like i have done in the lower left of your image and it reveals that the moon is, in fact, orange! This is also consistent with a with an image of a movie (A Grand Day Out) that i have found and which was shot on the moon (right illustration). Some might argue that this might be an animation movie, and they could be right, but it should be noted that this movie was from the 80s; they did not have the computer technology back then to make whole virtual planets, so they must have had used the real moon for this.

i'm starting to get confused as to whether this thread is answering my original question or if it is becoming a battle of opinions..........never mind........but thanks bb

Attached Link: archangel gabriels batman

Sorry if i have confused you, but to your question:

1. there is practically no difference between terradome and skydome, and various other ...domes you might encounter (one comes with poser in the primitives section).

2. as bagginsbill pointed out, there is no significant difference between sun and moon if you want to have realism. And since you use a moon prop, you could probably do without any X-dome at all. But because your moon is visible in the render, you probably should make it the lightest object in your scene, it should be lighter than the stars, for example. Your problem is, that you are doing an against-the-light image, so if you want to go somewhere near realism you either will not see the face of your character (because it is too dark), or your moon will be very bright (see the linked image as an example, even though it was not created with realism in mind).

No you cannot simply subtract. First you have to take gamma correction into account. That photo is not recording linear values - they are sRGB values. This really matters here. You cannot directly perform addition or subtraction of sRGB values. You must use linear values.

Here is my screen shot from Poser Pro where the material room has automatic GC. You can see quite clearly that after removing the blue glow from the atmosphere, the moon appears yellow, just as I said. I also used an HSV node to amplify the color and make it more obvious.

Now it is not actually yellow - it is gray. It is the sun light that is yellow.

Also, before we do any more of this, everybody please pay attention to this simple fact:

The color of photos is arbitrary. There is an element to the internal processing called white balance and unless you undo that you cannot actually find the true colors.

So logically, when the moon is lower in the sky and looks yellow/oragne, that is actually closer to it's real color?

Its real appearance is yellow or orange. Its real color is gray.

What you see is the product of the light color and the moon color.

Did you find my explanation of what you see versus what it is unusable? 

It is yellow light bouncing off gray rock, and so it looks yellow. When that passes ghrough blue sky, some blue is added to the yellow making white. But there is less blue close to the horizon, and the passage of light through a lot of atmosphere removes blue and green, leaving more red, thus it looks orange.

There are many atmospheric situations. Ever hear of a blue moon? 

mystic, the last render looks good IMVHO.  went outside just now and the moon appears slightly yellowish overhead.  in accord with the policy of not posting jokes here, may one mention that a blue moon is when there are two full moons in the same month?

what i really love about this forum, is that you learn from your own mistakes and other peoples experience, i suppose i have been a lazy artist, relying on 3rd party and proprietry preset lights far too much, i suppose i could blame it on lack of time, but when i consider how many renders have finished up in the recycle bin and the hours i have spent, it makes sense to experiment with your own lighting . I guess like many artists, lights and mats have been almost one step too far but i'm encouraged now to do some more research and hopefully produce some excellent images. thanks to everyone for contributions and comments.............

http://en.wikipedia.org/wiki/Blue_moon

Quote - Wiki - A blue moon can refer to the third full moon in a season with four full moons.

Quote - Miss Nancy - a blue moon is when there are two full moons in the same month

Both are correct - it amounts to 13 full moons in a year. For this to happen, it is necessary to have four in a season and two in a single month.

However, there are lots of months with two full moons that are not blue moons because there are still only 12 in that year. This is a simple consequence that a lot of months are 31 days.

So - a blue moon is not defined by two full moons in a month but four in a season or quarter.

In any case, it is rare.

Furthermore, what I was referring to as atmospheric events is described in the wiki article:

Quote - The most literal meaning of blue moon is when the moon (not necessarily a full moon) appears to a casual observer to be unusually bluish, which is a rare event. The effect can be caused by smoke or dust particles in the atmosphere, as has happened after forest fires in Sweden and Canada in 1950 and 1951,[10] and after the eruption of Krakatoa in 1883, which caused the moon to appear blue for nearly two years. Other less potent volcanos have also turned the moon blue. People saw blue moons in 1983 after the eruption of the El Chichon volcano in Mexico, and there are reports of blue moons caused by Mt. St. Helens in 1980 and Mount Pinatubo in 1991.

I start with three blue pawns on a gray plane.

Lit with a single white light, we see the color of everything and can verify that the pawns are identical. Why?

What we see (S) is the light color (L = gray-white) multiplied with the object color (C).

For the pawns it is:

S = gray * C

since gray-white is neutral and equal amounts of RGB, it does not alter the ratios so it is a constant:

S = k * C

Therefore, what we see is the true color of the object but changed in brightness.

We can say that:

HueOf(S) = HueOf(C)

The apparent hue is identical to the actual hue, when gray-white light is used.

What "color" is each pawn, now? Is it the same as each other and same as before? Well, actually, yes, the color (C) of the pawns is the same as before.

But the apparent color (S) is different, and not only different from the previous render, but different from each other in the same render.

We can no longer tell at a glance that these are blue pawns.

I add a blue glow, similar to atmospheric glow.

Guess what - the yellow and red are not those colors at all. Everything is mostly blue - go ahead and measure them. Blue is the brightest of the three RGB values nearly everywhere in this render. (Perhaps it is everywhere - I did not sample every pixel.)

Despite the fact that I'm shown mostly blue, I distinctly "see" yellow and red.

Neither of these colors is yellow.

i've just been re reading, and i notice willyb53 talked about adding the depth cue background, how do you achieve that? and let's say for instance i wanted to enhance the image by adding a hanging lantern or two from the limbs of the trees, to give an elven glow, i've tried upping the ambient value on the flame mat setting, but the light from it is very harsh and artificial, are there any tweaks i can make in the mat settings to soften the harshness and add more realism?

By introducing some additional light in the foreground, you create a contrast with the background, so I'm not sure that you would also need to use depth cue.

On the other hand, depth cue can effectively force a foreground/background contrast in otherwise even lighting, so could be handy.

I'll show you setting up the depth cue momentarily.

First, a little explanation of the lantern.

I placed a pointlight inside each lamp, near the top. These are my "bulbs". They are set to inverse square falloff.

The lamp "glass" is a nearly transparent material. Transparency is .98. That leaves 2% of local lighting. With the point light so close, the glass is intensely bright even at 2% reflection. It looks white.

But the bulb point lights are not white. They are yellow. I used the front parameter dials and the RGB value is 1, 1, .9. Intensity is 70%. (0.7 in the mat room)

Shadow blur radius is 2 at 50 samples.

Note also that the local lighting creates a gradient bottom to top  as well as front to back. If we were to use depth cue instead, it would only be front to back.

I prefer the realism that comes from local lighting.

i'm all eyes n ears BB. this is really most appreciated ty

This is the same as before, but with the "moon" turned off. I show this so you can see how much the local lighting dominates the scene. This may or may not be important to you - that local lighting overwhelms the moonlight.

Keep it in mind.

I have read that due to phases and variations in orbit, the moons illumination varies enormously - like 20 to 1!!! And light bulbs vary in power by a lot, too. So I think you could plausibly get away with just about any ratio of local versus moon lighting that you want.

The key is that local lights (bulbs) are very yellow. More yellow, by far, than moon light. And a photo that is white balancing both local and moon light is going to shift the moon light to the blue side, very much. In the presence of very yellow local light, moon light will look extremely blue, even though it, too, is yellow.

Observe how, with inverse square falloff, the trees in the back are black. You don't need depth cue faking the effect. In old Poser before inverse square falloff, maybe you did. But I'll show you how to set it anyway.

Here I have done a very bad thing to my render. I have disabled shadows and added rather overwhelming global lighting via IBL. I have ruined it!!!

Wow.

In the material room, go into "Atmosphere".

Turn on depth cue and adjust the end distance. My units are inches, so I have the scene get gradually darker, until it goes black at 1750 inches.

You can change the start distance as well, and the scene will be full brightness in front of that distance, and only start getting darker from there.

But - nice as this is, it's an 80%-correct solution, whereas using IDL, inverse square falloff, and GC is a 95%-correct solution.

There are things that jump out at me with this render - things that would make me not want this approach.

The two biggest things wrong:

• the underside of the leaves at the top don't look right

• there is an artificial straight line on the ground where light just stops - pure black - that is where the cutoff at 1750 inches is forcing pure black. It is too obvious, IMO.

I notice that when going into the mat room to set the point light, there are two mats, the flaps and the base, do they both need setting the same? and without being too stupid you mention the inverse square falloff, i've read about constraints but have no idea where they are located in the settings....scrub that found em  lol.....i'm just playing around with the light effects you have talked about and i'm getting some really atmospheric effects cheers bb

Quote - There are many atmospheric situations. Ever hear of a blue moon? 

Silly atmophereic conditions.  Changing the moon's color.  Making it look bigger or smaller.  No consideration for the rest of us.  And I thought a blue moon was 2 full moons in a months time and not literally the moon turning blue.  Someone needs to do something about these uppity volcanos. 

Nice illistrations though.

I've got an astronomy background, so maybe I can approach this a little differently for people who aren't quite following where BB is going...

The sun produces what is, for all intents, white light.  The moon reflects the sun's light essentially equally across all wavelengths, so the light coming off of it is still considered "white" light.  (BTW, the moon is actually a very poor reflector of light--only about 9%.  Even though we see it as gray, it's really no brighter than freshly paved asphalt)

Now the light reaches the earth's atmosphere, where some of it is scattered.  However, blue light is scattered more than the longer wavelengths (a phenomenon known as "Rayleigh scattering").  The result is that some of the blue wavelengths coming from the moon are removed from the "direct" moonlight, and used to light the sky--it's why the sky is blue in daytime, and even a very dark blue during a full moon.

When you take some (not all, but some) of the blue light out of white, you get a slightly yellow cast to the light.

As the moon gets lower in the sky more light is absorbed, making the moon look yellow, and then orange once it's low enough that it begins to absorb noticeable amounts of green as well

Attached Link: shadow catcher

You do have a lot of artifacts appearing at the seams of the column textures; that blue glow might also be much of the same.