Tuesday, October 6, 2009

Light and You!

You might wanna make yourself comfy. This is a long and informative post.

Let's talk about light. The SL Knowledge Base says light

"Only six lights are supported for hardware lighting. The shaders support eight lights, but one is reserved for the sun or moon, and another for a 'backlight' which approximates reflected light from the sun or moon. The list of lights used is determined as follows:

  1. A list of nearby lights is generated.
  2. This list is calculated once per frame.
  3. Six lights are chosen from the list. Priority is based on the effective intensity of each light at the viewer's Avatar. Dynamic lights are given slightly higher priority.
  4. For each object:
    • With the 'Nearby Lights' setting, all lights are always used."
This means that only 6 sources of light will be rendered and they are usually the ones closest to you. So if you have 8 balls o light hovering around your head, you are pointless. Yay You!

Lighting Tips

There's a lot of versatility in the lighting system, so be creative, experiment extensively, and keep inventing new uses for lights!

  • If you set Intensity or Radius to 0.000, or set the light's color to black, you might as well uncheck Light because it's visually the same as turning the light off.
  • Remember, ANY prim you've made can be turned into a light. No matter what shape or size, its light properties can be set independently.
  • If you want your object to be visible in the dark, but not give off light (like a computer monitor or a soda machine) you can check the Full Bright checkbox on the object's Texture tab.
  • Lights in motion are dynamic and follow their source prim. For example, carry a lantern in your hand and find your way in the darkness. Or use light prims in a vehicle, perfect for adding that film noir touch to a skittering airplane. Physical objects can also be lit: roll a big glowing red ball down a hill and giggle with glee!
  • Common sense: the darker it is around you, the more lights will stand out. If it's high noon, you won't see many lighting effects, but as dusk approaches, the local lights will increase.
  • Like other special effects in Second Life, use lights wisely. Please don't light everything; it not only diminishes the highlights and contrast that a few finely-placed lights can add, but it also slows down performance for yourself and fellow Residents too.
  • Why six realtime lights, as mentioned above? Because the OpenGL specification which SL uses allows for eight lights in a scene. Specifically in this case: six lights, one for the sun/moon, and one for the backlight representing reflected light. Static (non-moving) lights will be "baked" so you can still see the effect they have on the area. For this and more behind-the-curtain details, please see the related OpenGL technical document.
I think I might even tattoo that on certain people's foreheads. Oh BTW. I'm really good at knowing you're wearing stolen hair, shoes, or other items.. you know how?
This is my friend. Advanced - Rendering - Info Displays - Light. It will show you every prim in the area that is giving off light. It will also show you a yellow cube of how FAR the light is radiating.

This is me.. this is me showing you stolen hair! Yay! Wow.. you learned something NEW today.. enjoy!


Sorite Krautrauch said...

I adore this post and have sent it to many friends. I found so many things that were lighted that didn't need to be. My kids bought my hubby a car for father's day and it was lit up like a light! I know it wasn't stolen ( at least not by them) but i had to go through and unlight at least 30 prim. TY TY TY

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