Prim flicker

Prim flicker, also known as Z-fighting (see technical definition), is a common graphical annoyance in Second Life. It appears when two faces share the same surface space — in other words, they're fighting for what appears, and as a result, look ragged and almost crosshatched. You can easily reproduce this:

1. Rezzing two cubes next to each other such that their edges along two coordinates are the same.
2. Give each one a distinct color.
3. Intersect them slightly and move your camera.

How do I work around Z-fighting in Second Life?

There are several ways to approach this, depending on what you're doing. Usually, you can simply offset one prim slightly,, such that it appears almost level with an adjacent prim, yet is distant enough to avoid Z-fighting. This video shows how that applies in the context of building a bridge across Region boundaries:

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Why don't I see Z-fighting in other 3D experiences, like games?

We'd need to look at a specific case to detail why. Generally, some game engines are designed with workarounds to minimize or avoid the visible effects of Z-fighting. In some cases, that may mean that Z-fighting is still present, it's just obscured. In addition, professional computer artists know how to deal with Z-fighting when they see it.

In Second Life, much content is created by enthusiasts who aren't necessarily graphic programmers. In response to other games used as examples for "Why can't Second Life do this?" BigPapi Linden wrote:

Everything else you mentioned is a perfect example of the things that you can do when you have professional artists working in a structured environment on art. We have an open system where close to all of our content is created by amateurs in the public at large and where we don't place many limits on the efficiency of the content they create. So yes, of course a modern AAA videogame looks better than the average SL scene. Professional game artists (which Bethesda's most certainly are) are simply that good and their engine has been created to perform well and look beautiful, not to allow anyone to dynamically create any content that they want with few limits.

That's why it's beneficial to educate Residents about what Z-fighting is and why it isn't a straightforward fix, but requires more insight.

See also

• Prim textures overlap strangely when transparent textures applied - A related prim flicker involving textures using the alpha channel. Picture examples and lots of related discussion towards furthering understanding in the comments.