Introduction to Lighting for Poser and DAZ Studio

If there were one thing I would say you should take away from a conversation about what makes a good 3d picture–or any representational art–it would be that lighting is utterly crucial. Lighting is definitely one of the most basic things you can learn in 3d, and it will also help you in any visual art. In fact, 3d is one of the best places to learn about lighting, if you have the software, because you are not limited by your studio space and real physical light setup. All you need is your computer.

I can’t speak to any programs but Poser, but if you want the definitive book on digital lighting of every sort, go get Jeremy Birn’s book: Digital Lighting and Rendering (Second Edition).

Back in January, a lovely lady asked in the DAZ3D forum about lighting, and another user and I did a five-page tutorial thread which is still quite useful. My intention is to pull material from that thread (what I wrote) and post it here.

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Jasmine wanted to know how to do something like this promo picture for Carrara 7. Please note, this is not my work. It’s from DAZ3D.

Carrarra 7 Pro promotional image

Carrarra 7 Pro promotional image

Let’s analyze the promo pic for a moment.

First, I know I sound like a broken record, but Runtime DNA’s Render Studio is an excellent buy, both for the many lighting choices and the tutorial on how to use them. )I am not familiar with the pw– products, so I can’t speak to those.)

Keep in mind, you must use Ray Tracing renders (in Poser)to do what I’m going to suggest.

Here are questions you need to ask yourself

1. Where is the main lighting source?

Well, the sun, in this picture. By the woman’s shadow, it’s above and slightly behind her. This gives strong shadows and a nice bit of edge lighting on her hair.

2. What about other light sources?

There is some ambient light that shows details in her dress and the leaves under the trees and so forth. Ambient light is not from any particular source, theoretically. It’s light that bounces around in the scene, puts detail into shadow, and keeps things from looking flat and two-dimensional. A lot of it is coming from the sky (not the sun) and is also reflected from the ground.

If there were shiny or otherwise reflective things in the picture, you might also get lights on her from them as secondary light sources, to be perfectly accurate.

How to replicate that?

Well, that’s the issue in 3d applications, and it can be achieved in various ways using both lights and shaders on the objects.

I would recommend, were I trying to replicate this in Poser (if I had all the wonderful models and vegetation, et cetera, available) by:

1. A bright spotlight or infinite high above her as the key light (try both and see how you like them). This single main light in the scene is, as its name suggests, critical/key to the lighting. it will always cast shadows.

If you use a spot light, make the outer angle very wide, at least 160 degrees. But since the whole scene is lit, I’m leaning toward trying an infinite light. Make sure this is the one that casts shadows–only–and they should be soft shadows. In the light properties tab for your key light, try a 4 to 8 radius and the rule-of-thumb 0.330 shadow bias. Intensity of 75% to 90%. You want some softness on the shadows, otherwise the light will look very fake and harsh. Set shadow percentage on the Attributes tab to 0.8 or 0.9.

2. Then I would have an IBL (image-based light) to simulate the ambient light. Don’t know how IBLs work in Studio. However, they simulate a sky dome and the light reflecting ambiently from a scene. IBLs do not cast shadows. Set brightness to 30% to 50%.

IBL or similar ambient lights keep your figures from looking like plastic dolls.

I have since seen some recommendations that if you use IBLs, the percentages of light intensity should add up to 100%, with the IBL being betwee 40% and 60% of that.

3. A nice warm orangey-yellow edge light for her hair and shoulders. This is a bright infinite light that casts no shadows in Poser, and is pointing from back to front at about a 45 degree angle downward for this pic.

4. That’s the lights. Now you need the Ambient Occlusion shaders added in; there are scripts that will do this.

I think BagginsBill (??) has some excellent tutorials on what AO is and does for you. In a word, it is the soft hint of shadow you see at the edges of an object that is cast by other objects nearby. It should NOT look like a dark line around everything it’s on! If it does, your people will look like they’ve had a fight in a coal bin and gotten a black eye.

For best results, I would only add it to textures (not to the lights, that’s usually too strong) that are showing on figures you need to be grounded. Hair and background elements tend NOT to need it. Sometimes a test render is required.

For most skin/clothing I start with:
Samples = 3
Max Dist (in poser) of  3 inches
Ray Bias = 0.4 inches
Strength = 1 (this setting really doesn’t matter, in Poser)

For the face and/or very small objects (eye white/sclera, lacrimal, eye socket, lips, face, nostrils, buttons, thin trim or ornament):

Samples = 3
Max Dist = 1 inches
Ray Bias = 0.01 inches
Strength = 1

NOTE: You can indeed add AO to the lights if you want everything in the scene to receive the same AO value–but be VERY sure you want that. You can add AO to the lights in Poser in the Properties tab for that light. You’ll only need to do it for one of them. And, I would not add it to the IBL light if you are using one, as that tends to look pretty bad.

5. Other shaders/materials: something to add a diffuse glow to skin if the IBL doesn’t do the trick. Why? Because if you don’t use them, you get the flat plastic doll effect you see in bad Bryce renders. Laughing

The skin realism shader sets you see for Poser 6 or 7 (Face_off’s Real Skin Shaders, for instance) take care of simulating the translucent quality of skin. In older Poser versions we added a little ambient light (fake glow) to simulate this. If you have a render engine capable of using IBLs, don’t use this ambient, or use VERY little, otherwise your people will look very weird and alien. Laughing

Please note that I’m classifying and analyzing at this point, not necessarily telling you in what order to do things! That will come later in the discussion.

Lighting elements

I categorize them in priority order as:

1. Key lights
2. Fill or ambient lights
3. Specular lights
4. Special effects

This terminology has its origins in photography, I believe. It’s certainly not original with me! (If anyone else finds errors, please correct me.)

This is about lighting a composition. I paint still lifes, too, and that’s where I’m coming from here, as contemplating a setup on a stage of sorts, framed by the edges of your render/preview window.

1. Key lights

These lights will produce the main highlights and shadows that inform the viewer’s eye about the dimensionality of the object and give it solidity and depth. Yacomo’s first ball on a green field shows a basic key light setup.

In Poser, you can use a spot light for this, most times, with a wide end to it, like 140 or 160 degrees. Point lights can also be used to very good effect. (Note: since I first wrote this, Blackhearted and Synthetic have published a *fabulous* set of lights called, “Pro Studio,” that use point lights.) Classical composition teaches that if the figure is standing in front of you, the key light should be 45 degrees to the left or right of the figure’s midline (nose and bellybutton) and 45 degree upward. It will be pretty bright (between 75% to 100% of maximum possible brightness). It will be set to cast moderately sharp shadows. If you want, you can use Point At in Poser, for spot lights and point it at the figure’s chest. This generally works pretty well.

For our reference here, a key light that is to the figure’s (not your) right is a Key Right. A key light to the figure’s left is a Key Left.

You *can* just light the scene with a key light, as one would in an indoor studio, for a very dramatic look. However, much detail on the texture and figure is lost because, well, it’s just too dark. The shadow is too overwhelming.

2. Fill and Ambient Lights

We need some detail in the shadows or, more probably, we want to see some detail at the part of the figure that turns away from the light and into the shadow–this is where most textures and colors show themselves and the interesting bits of the model show up.

A very harsh key light has a very narrow zone where light falls off very quickly to dark. Your figure looks quite flat and maybe even toony. (Sometimes that’s OK!)

A key light that is too soft has barely any highlight. It may not be bright enough, and everything looks too dim. (Sometimes you want it this way for special effects, though.)

There really is no “right” and “wrong.” However, you will usually want to set up your Key so that the part of the figure that turns away from the lightest part to the darkest part is as large as you can get it without sacrificing either the deepest shadow or the lightest light. Smile Well, as a painter, this is what I learned about lighting things.

However, in 3d lighting, you have to provide your own helpers to get a decent transition from light to dark. Therefore, we use Fill or Ambient lighting.

Now, Ambient can also refer to a shader property of textures. I’m not talking about that right now.

Fill lighting can be real simple. Add an “infinite” type light in Poser that is set to 40% of maximum or less, and have it pointing in the direction opposite to the Key light. Some detail should now be showing in your shadows, and the light-shadow transition is not as harsh as it was.

Ambient lighting, as I mentioned before, simulates the “natural” light that bounces around in well-lit areas. That’s why in sunlight we see the bright tops of things, but if we look underneath them, we can still see detail and shapes.

In Poser 4, we had to simulate ambient lighting with about a zillion small spotlights that studded the scenes like porcupine quills. Now we can use ONE IBL light (HDRI or otherwise). IBL image “textures” are actually made from real scene photographs, in some instances. It gives the effect of the “looking under the table” experience. They are not resource hogs (unlike the zillion small spotlights) and that’s why we love them. You have to use ray tracing to use them, though, I believe.

But, thinking about dark and light, there’s the one thing that REALLY tells us about the texture of an object, and that’s its specularity.

3. Specular Lights

Specularity of an object (and you can fiddle with this node in Poser on a object’s texture shader) defines how we percieve the roughness of a surface. Skin and velvet have very dispersed specularity because they are lots of itty bitty tips of shiny surfaces (take a good look at the back of your hand under strong lighting). Metal, glass, and shinier things have strong, condensed specular areas.

If we were painting, the roughness of that brightest spot is where the texture (surface roughness) is crucial in characterizing a surface. So we set up those shader nodes accordingly. However, if we do not have a light for the surface to respond to…well, there go the good intentions.

Our key light takes care of much of this work. If it doesn’t give you a decent highlight on its own, it’s not bright enough.

Yet, we may still need an accent light to make textures pop. We want eyes to glint, steell to have a gleam, and silk to shine, probably more in a picture than it would in most real life situations.

This is where we add a specular light. It’s not really a special light, except that it is a 100% bright light that comes from generally the same direction as your main light, is an infinite type light, and casts NO shadow. It’s only purpose, and it should be added last, is only to provide those glints.

Light your scene without the specular lights; add those last.

4. Special Effects Lights

Last in my introductory tour are what I have blithely referred to as special effects lights. They’re not so much unusual to use as they can really make or break a scene.

When we’re observing how light acts on objects, we see a couple of kinds of light that seem to come from the edge of the figure or object. One is backlighting, such as you saw on the hair of the woman in your example picture–makes her hair and skin (shaders) glow, illumines an object or figure against a darker ground. They really add to a mood–I’m probably over-fond of these rim lights.

Rim lights are often spotlights that are much brighter, of necessity, than your main light, but because they are not shining on a surface you see much of, they serve only to illumine the curve of the figure as it passes away from you. They will be 150% brightness (don’t ask me, it’s Poser’s system) and will not cast shadows.

An edge light is also effective, if more general and subtle in its application. You can use an infinite light that does not cast shadows, shines on your subject figure from the rear, and is about 200% brightness or greater.

One important use of an edge or rim light is to provide particularly bright reflected light, such as you see on the ball in Yacomo’s fourth ball render. Look carefully: it is a subtle light on the back of the ball, ostensibly reflected up from the surface the ball is sitting on. This adds a great deal of realism, but you have to be careful not to overdo it.

Additionally, you can have “gobos,” as they call them in theater and film.  You could cast a shadow or a light shape–like window blinds or a window shape.

And you can have “hero” lights–like the Hero F/X package provides, which provide focus in the piece –a pot of fire, a candle flame, a window, a magic effect…and so forth.

Back to Key lights again for a second: I’m back home and looking at Render Studio in Poser, and I see that one of my favorite setups uses what is called a Soft Box. Sounds comfy, yes?

But in this case a Soft Box is a group of four spotlights tightly clustered in space with a controlling light that the others are parented to. None of them is more than 25% bright, and the control light (the fourth one) has something like a shadow blur radius of 5 and a Shadow min bias of 1 (way higher than you should usually use on a single spotlight in Poser). The other three do not cast a shadow. This gives a nice studio-type effect.

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After lights, you get into the matter of shaders and how they interact with lights. Birn’s book (I have it right here) goes into excruciating detail over how and why to light and add shaders, more than I can.

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Thanks to LT Roberts for setting me straight about the gobos. Render Studio’s how-to PDF calls them “gels” which isn’t quite right (gels just color lights). Go figure.

Resource Summary

Digital Lighting and Rendering (Second Edition). , Jeremy Birn.

Runtime DNA’s Render Studio

Pro Studio by Blackhearted and Synthetic

Real Skin Shaders by Face_off

Hero F/X Extreme props by Netherworks

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