What is it with light...

Guys, how do I get light to work?

I want to make a lamp. Easy, huh? I make a round ball, make it white, and make it "light".
The ball seems to shine while I move it in the edit mode. But, once I stop editing it... it stops shinning. It's just a white ball... no light. What am I doing wrong???

That's really strange, Marker. It's easier to see the effect of Light in nighttime, and with Local Lighting turned on if possible. You aren't confusing this with the yellowish "select object" glow, are you?

The amount of light emitted by an object with the light attribute set is controlled by the size of the object. A small object won't put out much light at all. If you're trying to light up a room, a small lamp won't do it. Use a small object for looks, use a big invisible prim set to light to produce the actual light. This technique looks bad for people who have the "glows around lights" option enabled though.

It's probably too small (the light part)

What you can do, is make a larger prim 'light' and make that prim invisible, so that it has more of a light effect and looks the same as an actual object.

But, lighting in SL sucks anyway so dont worry

Uh yeah, what chip said (he beat me to it)

Hmmmm... the small thing makes sense. I'll try it out.

They should allow you to specify the "luminisence" of light objects...

Then again, they should also allow you to specify the "mass" of objects, so you can have a little heavy object that reacts to applied force accordingly when set to physical.

When you say to make it "invisible", you mean a complete alpha texture... or some hack the community has come up with?

just a fully alpha texture

Changing the composition type of the object changes its density, and thus its mass. Metal objects weigh more than wood. I often hollow out objects so they aren't so heavy too.

I have noticed that the 'light output' of objects will dramatically increase when I move them in edit mode, although this is an intermittent thing.

That's exactly what I've been experiencing!

Thanks guys... your advices have helped me alot. I just wanted to know if I had any configuration problems, and now I have a full blown solution to my problem!

When you're editing a "light" object, the lighting is calculated by your graphics card -- it's much faster that way, but less accurate. Once you stop editing it, SL switches over to its internal lighting model, which is more accurate and can handle more lights.

Actually yes there is a way to make it completely invisible with a quick bit of scripting:
Create this in your Script inventory not in the object, then in edit mode choose select Individual, drop into any prim that needs to be invisible.

default
{
    state_entry()
    {
         llSetAlpha(0.0,ALL_SIDES);
         llDeleteInventory(llGetScriptName());
    }
}

(uncompiled since I'm at work but it all looks right)

L8r,
UU

My experience is that script will give you 95% transparency on all sides of the object.

Actually, llSetAlpha() has been changed recently, and will allow full 100% transparency (llSetAlpha( 0.0, ALL_SIDES)). The transparency setting available in the texture editing window is still limited to 95%, however.

woot! That resolves something I have been thinking about.