This conversation has been coming up a lot lately, so I thought that I would write about it. The use, misuse and full understanding about lighting in Second Life, mostly as applies to facelights and etiquette, but can also be applicable to photography. Why do people wear so many bright facelights with a tremendous radius? I suspect it’s simply because they don’t understand the inner-workings of how Second Life works, as well as not really having been informed as to what the social impact is. It’s NOT an all or nothing thing, we don’t need to go on a witch hunt, we simply need to make a bit of knowledge available. That’s what I’m hoping this article will provide.
Note: All of these images are clipped from the top, hiding the menus. This was the result of batch processing without thinking. It was also a quick and convenient way of hiding personal information. Hopefully, the location of all relevant menus that are pulled down can be discerned when comparing to your own client. Additionally, some of the screen shots are messed up with odd bits such as lines and double title tags. You can thank my video card for that. It does that when taking snaps with the UI turned on. Sorry about that.
Facelights are a two edged sword
On one hand we want to enhance the appeal of our avatar, to see it in dark conditions and to generally highlight our best features. The pros and cons: The Pro side will make comments like this: “I just want to look nice, and remove the harsh edges from my AV”, “The lights enhance my look”, “Everyone tells me I need a light, so I got one.”.
The Con side might say something like this (copied near-verbaitim from unidentified freebie face light merchants): “Ever sit in a dark place, enjoying the scenery or perhaps a particle show, when someone with a facelight geared for disturbing fauna several miles away walks in and spoils the scene?”, or “I made this due to seeing some horrible facelights, so here you are, a face light that lights your face and chest and not the whole area…”
While it’s true that a facelight can really enhance your look (I often use one personally, and as a photographer, I use them constantly!). The trick is to use the facelight in a manner that in fact enhances your look, that doesn’t wash it out, or blind others. We want to make the best use of our light that we can without being light spammers.
Witness one of the very many examples that were the inspiration for this article. We shall name our subject Facelight Fanny.
Other that turning off the lights that belong to a build, other avatar’s lights and splashing them with an overly powerful light, there are other disadvantages, such as
Overly bright lights interfere with builders
A bit about how lights in Second Life work:
- They are all based on what OpenGL, SL’s rendering engine permits. OpenGL permits 6 (six) lights to be displayed simultaneously. Not one more. (Note: Technically, it’s 8 but one is reserved for the sun, the other for the moon. We have 6 lights that are directly usable to us).
- When lights overlap, the light with the highest intensity (the brightest one) wins and “turns off” the others in proximity.
- All things being equal, the last light will dominate.
For most of us, a light is is a simple prim that has a feature of light being check on. That simple.
A light has four potential values: Color, Intensity, Radius and Falloff.
Colour is… the colour of the light being emmitted. The colour changes the colour of the the light, and while it does interact with prims and textures, it does not change the colour of prims and textures.
Intensity ranges from 0 (totally off) to 1 (full blast). Intensity = brightness.
Radius, is measured from the center of the object to the outside. So, a sphere with a radius of 1 meter splashes light for 1 meter from it’s center all around, that means that it covers 2 meters of space in ball (all directions). It goes from 0.1 to 20 meters
Falloff is how quickly the intensity decays. 0 fall off means it’s full blast from center to edge. Falloff does not affect the radius of your light, it just makes a “gradient” of brightness from the center to the edges. The greater the fall off, the weaker it is when it’s away from the center If you had a falloff of say 1 (that’s 50%), the light starts to decay from full blast to totally of at 50% of the radius. So 50% of the radius is full blast, then it starts to taper off. My friend Loris Talon guesses that “it should decay with the inverse of the square of the distance”. It’s value are from 0 to 2.0.
Note: I’m not sure why the maximum falloff value is of 2. I’m guessing that it’s a 1 to 1 with the maximum radius of 20. So for each .1 we have a fall off value of 10% of the distance from the center to the edge. Based on this guess, I think the simple math would be that 0 is full brightness no gradient to the edge of the radius, .5 is one quarter way from the edge, 1 is 50% of the way to the edge, 1.5 is 25% of the way and 2 is 100% from the edge. Note that this is where the light begins to taper off. It always shines to the maximum of the radius. Confused? So am I. I’d love to hear from someone who knows better than I.
So, how does this apply to face lights?
Let’s start off with some simple things. For daily use, a face light serves to light up our face, so let’s put it about .25 meters away from our face.
Now. let’s get a sense of how the radius really works. This is one of the first ways lights are misused: not understanding just how far they reach.
Now, let us get a better idea of how the client actually calculates and figures out light sources. (This is also a great trick if you are being plagued with a light source that you can’t readily identify). If you do not already see your
Debugging Advanced menu, press Control-Alt D to bring up the bestest and funnest of all menus.
Now we see the light source, and the radius it uses. This is also a bit more useful for seeing the actual impact of the light. Also useful for users with different cards to see how light is rendered on another machine.
C’mon Quite! Quit exaggerating! Nobody really does that, do they?
Lights as we percieve them.
Other than being a simple study in one aspect of lighting, the point of beating this into the ground is that most people mistake “brighter” for “better” and now we shall see that under all conditions being equal, that there really is a threshold. Keep in mind that thes images are taken at midnight.
How lights interact in Second Life
Making your own facelight
Making your face light for those who have not yet done is the simplest thing in the world. Rez a prim. It’s pretty common for most people to make a sphere. It can be anything. .1 meters for x, y and z are good too. Large enough to be able to manipulate it when you want to, but not too much.
So we take our prim and the first thing we do is to name it.
Next, once we are editing our prim, go to the features tab in the object control panel, check the “Lights” checkbox, and adjust our lighting values.
The size of a prim does not affect the radius of a light. All light is calculated from the center of a prim, whether it be .1 meters or 10 meters, the center remains in the same location.
Light goes though everything. That includes prims and avatars. Nothing blocks a light source in Second Life. That’s just how the rendering engine works.
Lights are omnidirectional. You can’t make a spot light. I’ve often seen people fake them using prims, translucent textures and a touch (A touch! Do NOT make me write another article!) of glow.
I hope this article has been useful in clearing up some notions of how lighting works in Second Life, and I wish you a classy, attractive and well face-lit Second Life!