Light showing through walls

Wall that I build let lights show through. The light comes from objects with glow on or bright reflection on the water or the sun showing through. How do I prevent these lights from showing through the walls?

For now, you don't really :/ There is some shadow support in development, possibly for version 1.23, but we're not there yet.

I first noticed this about 10 months ago while trying to build a wall lamp. I uploaded a texture with a thin transparent strip in the middle, used this to texture a front panel of the lamp and noticed something strange right away. A prim immediately behind, whenever glow was enabled, appeared at supernova level wherever viewed through this front panel prim. I quickly discovered that the same applied to ANY texture with glow enabled - they all appeared, when viewed through any prim with this new texture applied, as this ugly, abstract, white-hot blob instead of being invisible as they should have been. Well it didn't take me long after this to discover that I could reproduce this effect when viewing any glow enabled surface through ANY texture with an alpha channel. I even tried with a (visibly) opaque texture with an alpha channel - same problem. I quick poll among friends found that just under half were experiencing the same thing as I was and the others didn't notice anything unusual. LL online support suggested I clear my cache or something equally inane so I just chalked it up to a strange and irritating glitch but this was quite a number of viewers ago and nothing has changed for me. I'll be interested to hear who else has experienced this. Klyks

The problem is entirely due to the texture having an alpha channel - even if the texture appears to all intents and purposes to be solid or 100% opaque.

I agree. Glow is a particularly nasty feature. As you discovered, it shines through almost everything and is visible from an incredible distance, like a thermonuclear blast. Worse yet, glow is apparently invisible to people using older viewers, although they seem to be able to create items using it. The sim right next to mine has a ghastly, tall building whose windows are all set to glow so the thing is blinding, even in daylight. We have complained, but the owners see absolutely no glow and are sure that we are harrassing them. You CAN block the glow with a prim that has a 24-bit texture (no alpha) on it. Blocking a gigantic glowing building, however, means putting up a megaprim wall ..... which is just as ugly.

And no, it has nothing to do with YOUR alpha texture. The disgusting building next to me is hanging right out there in the daylight with nothing between it and me. It's the glow.

As far as in-world "local light" sources go, like a lamp that emits local light, and also the light of the SL sun and moon, alpha textures have nothing at all to do with it. Light does not get blocked by prims or by terrain. Period.

As far as the reflections on water showing through a wall, yes, THAT is caused by an alpha textured wall. A 32-bit textured surface or a surface with anything other than a transparency of zero treats the reflections in Linden water exactly the same as any other 32-bit surface, and the alpha-sorting glitch applies. Which means you can NOT block the reflections, except by not using an alpha texture on the wall at all.

I have minimized that problems in builds by using a 24-bit wall texture and walls made of multiple prims, and only using 32-bit alpha textures for the actual window and window frame prim. Takes more prims, but looks far better if you have water, Linden plants, high heeled shoes, furry digitigrade legs or animal tails, or anything else that uses 32-bit textures or invisiprims anywhere near the wall.

http://jira.secondlife.com/browse/VWR-1017

Thanks, Argent. It makes interesting reading. All in all, though, I prefer to solve technical problems by going to the root rather than finding a way to hide them. It would be handy to be able to simply hide an offensive, glowing building, but the burden of hiding shouldn't have to be mine. There ought to be a way to cure the glow problem systematically at its source. I can't believe that my neighbors would tolerate their own building if they could see the thermonuclear glow -- it's a total, painful snow blindness -- but they can't, and they won't believe that anyone else can. The "cure" has to come in a client upgrade, once someone can figure out exactly what causes the problem.

Having had a couple of hours since my last post to reflect on things, I am beginning to wonder whether Ephraim (post #4) might be right that it's not glow alone, but a combination of glow and alpha that creates the problem. I discounted the idea before. Now that I think of it, though, each time I've seen a radioactive glow it has been on a window or some other object that is transparent. If that really IS the problem, is there anyone with a technical mind who can explain why?

I was thinking of the glow feature, in which case even quite remote objects will show through a texture with an alpha channel. I should have been more specific, I suppose, but I have long since taken the issue of sunlight show-through as granted.

You've sent them a snapshot?

Yup. They are in total denial. Since they can't see it with their own eyes, and can't believe that it's possible, they choose instead to believe that we have faked the photos. <sigh> As Lily Tomlin once reminded us, "Information cannot argue with a closed mind."

Tell them to turn on basic shaders in their graphics tab (check custom to see the option).

Glow is very difficult to use effectively. I am not sure what purpose it actually has. I have set 'glow' on a few items at 10%, then onto 5% and then taken it right down to 1% only. Anything greater than 1% causes a nasty spot of glare.

I only use 1% 'glow' now in building the actual bulb, (under a prim shade) on lightfittings, and for specific 'holy objects'; creating a centrepiece on the altar of my Sagrada Familia Cathedral for example.

I can't see any other uses for it. That building you describe must be hideous, I am sorry for you.

Best wishes from Ainee Kohime

Yes, glow is horrible, burning thru anything with an alpha channel. Anything more than 1 percent setting is just a griefers tool. It's disadvantages far outweigh any possible positive use. I suggest glow be repackaged in the next release, with a 1 percent setting as the new maximum.

I would agree the current strength of "Glow" is 100X too strong. It makes an illuminated sign look better at 1%. Maybe 2 or 3 is OK for neon tubing. But not much valid use that I have seen so far for stronger than that. It needs to be re-calibrated.

I have a neighbor with a huge glowing cube on his 512m2, which is for sale for the low-low price of 1 million Lindens. I'm all in favor of some sort of "muting" solution.

I'll bet if you submit an AR, it will be gone pretty quickly.

Reducing it would break content that uses the transmission effect.

Ah, I'd been wondering whether an AR would have any effect. I suppose I should try talking to the owner first, though?

Some extortion builds in Nautilus were taken down within hours. This seems a prime example of an exortion build.