Local Lighting

I personally do not like to use local lighting, but I recently built a house and wanted to see what the house would look like to those who DID use it. I was extremely disappointed. First off, there was a greenish glow to all surfaces facing in one direction. Where this green came from I have no clue except perhaps part of a green building set to LIGHT in the next sim. Also, sections of floors and walls appear to be dark while others appear to be light (no gradient, just a line down the wall.... dark on side of the line, light on the other). I checked to make sure that none of the prims were set to light, etc. but it looks really strange. Anything I am missing or any tips?

Thanks...

They might as well either MAJORLY overhaul this feature or get rid of it all together.

I used it once with the same results you described and it's never been checked "on' again.

Torley Linden seems to have had some fun results with it though. Mabey the 'Greenish glow" is an after effect of her ever beaming smile?

It's complicated, and as mentioned, doesn't work very well.

Light sources light up objects much farther away than they can be seen. That is, a light source will cast light on your prims from, say, 200m away (and from well into neighboring sims), but you will only be able to see the source, looking at it directly, from 50m or so.

You will not be able to see a light source if there is another prim blocking your view; but prims are totally transparent to local lighting (they cast no shadows on other prims -- but note that sunlight does cast a vague sort of shadow). So a light source hidden in a box can be very difficult to find.

I have chased down light sources by rezzing a cube and moving it from place to place to home in on the light source. If you find that a neighbor has prims set to light, you might have a conversation with him. Sometimes "full bright" works fine.

Light only falls on the vertices of the triangles which make up prim surfaces. Brightness is then averaged or bled onto the surface. For many small triangles (think SL spheres), this looks okay, but a 10x10 square surface is made up of two triangles. Try putting a bright light near a corner of a big square at night and you will see the triangles that make it up.

This scheme is intrinsic to OpenGL, but it means that unless you place prims carefully, you will see seams between them with local lighting on.

The implementation also has bugs (at least I guess so). If you top-size a square surface to zero (so that it is a triangle), the distribution of light will be different when it is rotated 180 degrees about the vertical axis. Go figure.

It seems like, by taking the time to get familiar with this behavior, you might be able to make something that looks good (like, don't use top-sized squares for triangles when cut squares will do); but I never got that good; and it seems that LL will start from scratch again soon, which means that all that investigation might be for naught!

Good luck if you decide to give it a go. IM me in-world if you like and I'll try and help.

--Allie

I normally have LL off, but I turned it on and found...

1. That a LOT of stuff that I thought was made of glass or metal was made of light... including a lot of gag attachments like freebie beer glasses and bottles. I turfed a bunch of inventory after that because...

2. It cost me about half my frame rate even when I was in an area where I couldn't see a difference bteween LL on and LL off. In "bright" areas like yard sales I was measuring seconds per frame and getting into two digits...

And I sure didn't want to be doing THAT to people around me.

And I don't think this is OpenGL's fault. LL could easily cull "light" objects and only set them as light sources when close to the camera and treat them as full-bright otherwise. And, really, the "light" rendering distance could be pretty small, 30m or even 10m or less, and still be plenty to simulate most uses of lighting.