Red, Green, and Blue Lighting dont mix

Hi there. I am trying to make an educational display showing how light mix to make new colors. I thought it would be easy enough to create three prims, each with a different value for light red (255,0,0) green (0,255,0), and blue (0,0,255). However, for some reason the colors don't blend. I think maybe that two at a time do, not sure. Any thoughts?

Anna

I think the main problem is, that in SL we do not see transmission of light, but only reflection. And reflection is even not fully implemented only approximated. No transmission means, that the light color does not get filtered while it transmits through material. While in RL this happens for transparent materials (light filters).

If you use three filters in RL (RGB) then the overlap off the three should become black (subtractive color model), because all light is filtered away (well almost all light

In SL you will get an additve color model instead, but since you can only look through objects, when you enable alpha (transparency) you end up with 2 other problems:

1.) You will not get plainb colors, but always a mixture between the background color and the object color depending on the transparency value. So you will never add the three colors to white, but to some grey value if you are lucky.

2.) Due to the known alpha texture bug, you will get a hard time to place 3 alfa textures on top of each other and get reliable results. It seems to work "sometimes" though.

The best you could do, is to select your darkest color as the top object (blue) but make it transparent ( ~70 %), then place a semi transparent red object in the middle ( ~50% transparency) and end with non transparent green object on the bottom. Then place a white plane below all of the other objects and make all objects "full bright" so that the ambient (environment) light does not modify the results.

Also note that the client controls which lights are seen, and the client only permits a set, limited number of atmospheric lights to affect the end result.

I think the total number is eight, including sun and moon. So six user-defined lights. Someone with three facelights will only ever see three other user-defined lights!

And some people don't have those lights on at all.

Demonstrate it the same way that they do in a print book. Use textures on prims, and not actual lights. SL Lighting isn't able to do what you're attempting.

/me waves to Anna, pondering her colors )

SL isn't actually capable of producing light sources in the conventional way. This isn't a lack in SL, but one in openGL itself. Games programmers use a lot fancy tricks in openGL games to make it look like proper lighting, but the real effect is more akin to a sphere around the object that does little more than increase the color level of the object it intersects with the color of the "light"

you can see the exact same effect in photoshop, just open a picture and then add a, for the sake of example, a blue layer above it and just slide the later opacity up and down and you will see almost the same thing you would doing it with a blue light and the same pic inworld