True Light physics

Light is one of my favorite things. Without it, there would be no life, people would wander around in total darkness, and most of the Builds in SL would be bland prims connected together, because without light, there would be no color.

So I suggest true light physics. I.E. light that acts as it does in RL. The light in SL is amazing as it is. You can subtractive color mix, so that you can create any color in the visible spectrum by using the 3 primary colors of light, Red, Blue and Green. Put a Blue light prim directly overtop of a green light prim, you come out with Cyan. Red and Blue, that gives you magenta or purple. I'm trying to create realistic lighting insturments for the globe theatre, and while the ability to subtractive color mix made me excited, i was a little crushed because i didn't have to specific abilities. As it stands, light only emits from the source to a specific degree, i.e. it only moves out a set distance from the parent prim. So that means that if you create a light ball, the light from the ball will only move out a small distance from the prim. The beam stops. This creates a problem as you cannot control the light very well. I tried placing a blue light prim in a parcan i built, but the light doesn't move too far from the insturment. I even tried reflecting the light off of a mirror surface, still nothing.

The other thing is intensity. The ability to control how bright the light moves and how far away the light can travel. As of right now, the only way to "dim" lights in SL if by changing the RGB value of the light. But this doesn't look realistic enough because the light spills too much. If I place a light prim inside of the parcan, the light stays in the parcan, but if I stretch the prim outside of the parcan, the light ends up spilling all over the place.

For now, i will simply use a cone, transparent, and in a color, made of wood, and place a light prim at the bottom exactly where i want the light to go.

I agree there needs to be more light commands. I'm surprised there isn't already, I was expecting there to be some light script possibilities.

I won't make any suggestions because I don't feel I've really expiremented with light enough to know what should be suggested.

The problem is that realistic lighting is unbelievably slow. Reflecting light off a mirror requires raytracing, which needs to be implemented in software: no video card supports it, and probably none ever will. Software implementations can take from a few seconds to a few weeks to render each frame, depending on scene complexity.

Most graphics cards can handle spotlights, but you can't count on more than eight lights being supported; more than that, and you're back to software rendering.

Better control of brightness would be nice, and would not slow things down significantly.

The size of the source prim effects the range/brightness of the light. So to light a large area, make a big prim... Invisible, if need be.

Remember, though, that objects in the world don't STOP prim light, nor do they cast shadows with it. The only shadows (if you turn that feature on) are fake ones from the sun.

A prim light only affects a surface if the surface faces the light. There are two light types I've seen in the game, directional and spot. The sun is the only directional light and all of it's light is going the same direction in parallel "beams". The lights we make are spots, and their light goes out in all directions.

When a surface calculates its current lighting (and again, this is only done if people have turned on that feature in their preferences) it finds all the nearby lights that it is in range of, gets the direction to that light, then compares that direction to its own "normal" (the direction that is straight out from its face -- up, if it's a carpet on the floor, for example). If its normal is within 90 degrees of the direction to the light, then it is lit up. If the difference is greater than 90, then it is facing away from the light source and doesn't add the light to itself.

That's the basics, I guess.

Yeah, i know size of the prim affects amount of light shed, but it'd still be nice to determine how far out the light goes from the source, an intesity setting. When i created a long beam of light, the light would spill everywhere, up down left and right. I figured out one way to do it, by creating a long cone prim, partially transparent, made of something other than light, i could place a light prim at the bottom of the beam, to get the light effect in a smaller spot.

I'm also scripting a rez object so the lights turn on when you push a button. It looks like you are turning on a light fixture.

I would REALLY like more accurate light effects.

For one thing, I just recently had to berate my downstairs neighbor in the SmartHouse Mansion because he kept leaving his lights on, and my room was like a sunbath even at night.

There are several layers of prims between our rooms, and at least two of them are solid with no cracks, but the light still shines through.

Yes, since prims don't block light, I always suggest making several small, invisible, phantom light objects JUST where you want the light to fall instead on one or two big prims, to light an area. This gives you much more control. Then you can make some small, visible lights that are just for atmosphere.

For a stage situation, I wouldn't put the lights where they go in a standard theater, but instead make them the small, invisible kind right at the edge of the stage just above actor head hight. Incorporate others into the sets for more custom lighting. I bet any stage director would LOVE to have that much control over light.

Yeah, that's what i'm doing tiger. I'm creating a "beam" which is actually just a wooden cone coming out of the light fixture. At the end of the "beam" is a light sphere, that actually casts the light.

Oh, and I try to use three-sided pyramid prims for my light sources, since they have the fewest number of faces and therefore slow the system down the least. I use them whenever I need a prim who's shape doesn't matter (invisible, really small, buried inside something, etc).