can anybody explain this (local) lights behaviour

[Jackson Redstar]

I have seen this a number of times I am wondering if there is a setting or something than can fix this. Seems to happen on textures that are semi transparent , In this gif below the shaders are on and Advanced lighting as well

https://i.gyazo.com/71275df06082bc480c4c729e7b57f764.mp4

 

[Paul Hexem]

If you have shadows on, turning them off might help.

That's just a different flavor of the old alpha sorting issue.

[Qie Niangao]

As a photographer you're probably already forced to run your viewer with RenderVolumeLODFactor cranked way up, otherwise it kinda looks as if a lit surface is reverting to a lower LOD, exposing a darker surface behind it.

Edited May 3, 2021 by Qie Niangao
["your" not "you"]

[Jackson Redstar]

I should clarify this is in FS viewer with shaders/ALM on - the LOD is set to default. Ive noticed over the years anything 'white' that has some alpha to it (like curtians, wedding dresses, etc) can just get weird and look funky in low light/local light lit scenes

[Aishagain]

Unless wiser council can tell me otherwise, what you see is the "alpha-sorting glitch" which has long been the bane of applications using the OpenGL code.  There is, as far as I know, nothing you can do about it.  It now looks a little different in the "Love Me Render" EEP render code but apart from that it's an old fiend.  (That was not, for once, a typo!)

[Qie Niangao]

The default RenderVolumeLODFactor seems to default to 2.0 in Firestorm (a viewer I rarely use), 1.0 in the LL viewer and in Catznip (where I usually run it at 1.125). I have seen creators (of bad LOD stuff) recommend settings as high as 4.0, which might be useful while taking photos. Not so much for video, though, because it will hurt frame rates. And may have nothing to do with this particular problem anyway, I don't know. @Paul Hexem and @Aishagain are probably right, I just don't remember seeing the alpha-sorting problem look quite like this myself. 

You mention ALM, and without ALM there's a whole different class of lighting weirdness that can mess up a scene because then light sources are limited to the nearest six, so moving around can change point lighting a lot. (You also said "shaders" when I'm guessing you meant "shadows" but I don't think shadows are related to this problem, and I think viewers must have Shaders on to even get ALM as an option.)

While we're on the subject: Has anybody else noticed that the alpha-sorting problem seems to trigger more easily with ALM enabled? Maybe it's my imagination.

When possible, creators can avoid alpha-sorting problems by making only one of the overlapping alpha surfaces use the "Blending" model. Lots of hairs come with alpha "Masking" layers interleaved between Blending layers, but that's no help in photographing an existing scene.

[Jackson Redstar]

thanks for the replys. there are so many hidden things in debug settings i was hoping maybe it was some simple tweak. and believe me as someone who has filmed dozens and dozens of wedding events under all sorts of lighting conditions and high lag, I have seen much strangeness and unexplainable behavior in SL! lol and since i only use FS there is no real help from Lindens and FS support is all but non-existent 

[bigmoe Whitfield]

Lighting with alpha bugging, meh,   turning off shadows (which should not be on anyways) and than basically having to get the camera right because of openGL being a derp.