Alpha Flicker

I am a hair designer in SL. I am sure you all know that apart from using a solid hair texture, many hair designers use a "cut-off" shaggy wispy alpha texture which you can use to make bangs or otherwise enhance hair.

My issue is, if i put more than one prim with alpha on it, it starts to flicker when you move the camera around. However i know tons of designers whose hair is 90% alpha and i cant find one damn flicker anywhere, so if there is a secret on how to make the flicker stop, can anyone tell me?

Hi Sarabi!

The trick is in the placement of the prims. For bangs, I have found that if you align them so that there is very little overlap between them, and a non-alpha prim behind them, the flicker is minimal.

But yes, tis a pain...but worth it.

~Ari

Cool enough I shall try it out. Always into learning new tricks, hehe.

just a little fyi.. there's a well know bug when one alpha'd texture is placed in line with another.. the client seems to have trouble figuring out which is in front of which, so, depending on your view (i.e as you move your view around), the 2 alpha'd textures will swap positions visually. That's where your "flicker" is coming from. It's a client issue, and at the moment, there's no way to "fix" it (short of rewriting the client!). Hoping they will eventually get around to addressing this issue.

I wish people would stop referring to this as a bug in the client. This is not some graphical error that LL has accidentally caused, this is a longstanding limitation of realtime 3D graphics. Without getting too technical, the videocard on your computer is capable of sorting the overlaps of opaque polygons, but not polygons with transparency. This is true of any 3D graphics system that relies on the videocard for 3D rendering (ie. pretty much any videogame.) The reason you don't see alpha flickering in most games isn't because of some magic technical fix in the game engine, it's because the artists who created the graphics for the game deliberately designed things to work around the limitation. They employed tricks like, say, the one described in the second post of this thread.

This is a specific case of a general frustration I get sometimes, how content creators in SL seem unwilling to accept the limitations of the system and design with them in mind, and instead expect some deus ex machina to save the day.

ADDITION: I am aware of a possible technical fix in the Torque game engine. I'm not sure exactly, as I've never worked with that game engine myself, but I recall reading once about something like BSP trees for sorting alpha transparency on characters. If that is even true, and I'm not sure, it certainly wouldn't be useful for SL, for the exact same reason that you can't edit arbitrary meshes in SL; that would be entirely too much data to stream in real-time over the internet.