Something needs to be done for any texture (whether image based or procedural) that has contrasty regular patterns, particularly fine parallel lines, like hair or a cloth weave, such as plaid fabrics. It does not happen when vieweing these things up close, such that the smallest features are larger than a pixel. It happens when viewed farther away, and some features line up with individual pixels to varying degrees, or when you get sometimes 1 per pixel, sometimes 2 per pixel, as they get smaller. This is a problem of under-sampling, below the Nyquist frequency, and occurs in all kinds of digital technology. In all cases, it creates artifacts - aliasing - the appearance or sound of things that are not there.

There are two choices for Poser users - super sampling or texture filtering.

Super sampling means to sample and evaluate the texture at many points for each pixel. To do this you decrease your min shading rate and increase your pixel samples in render settings. This will do the job, but it will cost you a lot. In certain scenarios, you will have to do more than 4X. You will have to do 9X to 16X. That means a min shading rate of .0625.

When the root cause of a moire pattern is a texture image itself, and not a procedural or geometrical detail, texture filtering is much more efficient. First it is only done for problem areas, not the whole image. That's a big time saving right there. Second, it is done in 2D so you don't have to fully evaluate the 3D shader.

Textures with no detail involving semi-regularly spaced repeating patterns do not exhibit moire. However, if we under-sample them we are distorting the details.

The thing is that most "natural" textures have details which are essentially random. Things like moles and freckles, the tiny wrinkles in skin - these are details that look just as good, whether under-sampling has distorted them or not. Do you notice when a little nick is taken out of a freckle? No you don't. But you do notice that the freckles as a whole seem less sharp.

IMO, the reason it seems less sharp is not a flaw in texture filtering, per se, as a technique, but in Poser's implementation of it. I feel that it is too aggressive at times, being tied to the min shading rate. If it had a separate control of its own for detail level, then I'd leave it on all the time.

As it is, I only use it for things like hair and cloth.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)