Raccoons like shiny things, and there's a bit of raccoon in each of us. The Second Life object primitive settings Glow, Full Bright, Shininess, and Light are attractive to raccoons everywhere, and can be used to good effect. But when misused, they can lead to problems. This article will describe what each of these settings does, when to use it, and when to avoid it.

To illustrate the effects, I made some balls. Then I put my balls on the counter and applied the various effects and photographed them. Here's a picture of my balls with none of these effects applied.

Glow

To whatever else a prim is, the Glow setting adds a wash of luminescence to the pixels that make up the prim in the rendered image. Glow tends to wash out any detail in the object, as though it were a lamp in thick fog. Personally, I find that a glow of 0.1 is good for something that needs to look like it's emitting light, such as a lamp or a mosquito trap. Avoid using Glow when there's text nearby that needs to be read: glow can destroy the readability of floating text in the line of sight. Glow is visible even at midnight when nothing is illuminating the primitive.

Here's a picture of my balls with Glow applied:

Glow is set in the Texture tab of a prim; it is a numerical spinner on the right under the Transparency spinner.

Full Bright

Under normal circumstances, Second Life calculates the brightness of any surface according to how much light is falling on it from other sources such as the sun, moon and nearby lights. So when the sun is down, less light falls on things and they get dark. Curved prims have different amounts of light falling on each part of the surface, so they have different shades from one spot to the next. The Full Bright check-mark turns off those calculations and simply renders that texture exactly as you'd see it if you were to open it up in an image viewer. This is highly effective for signs that you want people to read even when it's midnight. However, curved prims lose the smooth shading and will look flat.

Here's a picture of my balls with Full Bright applied:

Full bright is a check-box on the Texture tab, under Glow.

Shininess

Shininess is a primitive way to make something look like it has a smooth, reflective surface. This effect is created by automatically reflecting additional light from the surrounding area. There is some incident light from above the horizon and none from below. Shininess will hide detail in a texture by creating "glare", so don't make a poster, portrait, sign or texture with alpha shiny. If you set a prim's surface to have some transparency (alpha), then it will have no shininess.

Here's a picture of my balls all shiny:

Shininess is a pop-up menu on the Texture tab, below the Color spot.

Light

The emission of light is a property of any prim in Second Life. Light doesn't act the way it does in real life: In real life, a flash light emits light in a cone, and when it's shined at you you can see it. In Second Life, a light emits "light" in all directions, illuminating things nearby, but if you look at the light "source", you can't see that it is emitting light.

Here's a picture of my balls set to emit light:

Making a prim be a source of light adds computational load to the client computer that's running the Second Life viewer. The calculations of light emission and reflection are done in the viewer. The more light sources there are, the more calculations must be done. The effect of illumination is very subtle, and while placing light sources near each other may add only a tiny effect to the scene, they will add a lot of unnecessary overhead to every viewer.

OpenGL can only handle eight light sources in a single field of view. Two are used up by the sun and the moon. Any beyond that are not calculated, and it's not clear how SL decides which ones to calculate and which ones not. If you make something emit light, you may cause something more important to stop emitting light. If there are too many light sources in an area, it will be laggy.

At Black Gazza, people kept complaining that one specific area was laggy all the time. I did a light source survey and found dozens of light sources. I deleted all the ones I could and cleared up much of the problem. Unfortunately, a lot of toys, hairdos, and jewelry have unnecessary light sources.

My advice on Light is to use it only for local illumination when it's dark. For instance, at Black Gazza, many floors have a script that turns lights on when the sun goes below the horizon. Most of them only set the surface that has a texture with lamps to Full Bright and a little glowy. A few strategically placed ones actually emit light. They're set to as bright as possible with a big radius. At night, if you're standing next to one, you're illuminated.

If you're a builder, you should have the Advanced Menu on. Advanced > Rendering > Info Displays > Lights will show you all the things in your field of vision that emit light. Since light is calculated by your video card, not by the Sim server, everyone near your light suffers a performance penalty. I have seen jewels and hair that emit light, with dozens of prims, each carrying its ow little light box, to no good visual effect. Unless you want to illuminate an area at night, there is no reason to use the "Light" feature in a prim. There is never a reason to use more than one light-emitter in an object. There are many good reasons not to put a bunch of light emitters in one area.

Here's a picture of my balls glowing blue because the Lights menu item is on:

Here's a picture of Black Gazza at night with Lights information display on:

Here's a picture of someone with way too many light sources in her hair.

Light is a complicated setting with its own section in the Features tab. You turn it on or off (preferably off) with the check-box. You can set the color with a color picker, and intensity, radius, and falloff with spin boxes. Intensity you can set from 0 to 1. Radius is the theoretical size in meters in which the light has effect. Falloff governs how suddenly the light gets dim with distance.

Summary

• Glow - a short dash can make a lamp look like it's on
• Full Bright - use for lamps and signs
• Shininess - use sparingly but not for signs or windows unless you want to obscure
• Light - use exceedingly sparingly