Optical Illusion

was'nt sure how to title this..... what causes textured objects to to become trasparent and to just generaly do funcky things when viewing at angles ??

It sounds like you're talking about the alpha sorting glitch. When two or more surfaces with 32-bit (alpha) textures overlap in close proximity, the renderer has trouble determining which one to draw "in front". Generally, the one whose center point is physically closest to the camera gets treated as the "front" object, and the others fall behind it. This mathematical detarmination can often be at odds with what you as a human being consider to be "in front" or "in back" of what.

To prevent the problem, do two things. First, make sure you NEVER use 32-bit textures unless absolutely necessary. If you need a surface to have transparency in it, then and only then, use a 32-bit texture. If the surface is supposed to be opaque, ALWAYS give it a 24-bit texture. It's not uncommon for those new to texturing to assume that "more bits" must somehow be better than "less bits", so they put 32-bit textures on everything. Don't do that.

Second, build around the problem. Don't let 32-bit-textured surfaces overlap. If you've got a design that seems to require it, rework the design so that it doesn't.

The glitch happens in pretty much all video games and nearly all 3D modeling applications. Professional modelers and game designers will tell you the way they handle it is simply to avoid it at all costs. In other words, only use designs that steer clear of it.

Of course, the flip side of the glitch is that it allows certain things to be built "cheaply" out of just a few polygons (or in SL terms, just a few prims) that could otherwise take thousands. Without the glitch, the most common methods for building objects like trees, plants, and fire would not be possible. So, just so you know, even if the glitch could be fixed, there's serious debate over whether it ever should be.


For more info, see the transparency guide at the top of the forum.

thanks chosen.. yes i do have a few textures that 32 bit. and it just happens those are the ones thats giving me trouble