Should I change the transparency of the teeth by lowering the cutout opacity?

CHWT

Should I change the transparency of the teeth by lowering the cutout opacity? Or where should I do it?

To me lowering the cutout opacity of the teeth to 0.98 or 0.99 (without a cutout opacity map) seems to get rid of that hideous mahjong-tile-looking teeth. Maybe that's because the enamel layer is not entirely opaque? But I am not sure if that's the supposedly correct way to do it.

esha

It's not the correct way, but if it works, why not use it?

That said, Cutout Opacity is not supposed to be used at intermediate values. That property means a surface is there, or not there. It cannot really be halfway there. Like in lace fabric, you have some places where you have threads, and other places where you have holes. In reality you cannot have a half-existing thread. Since the slider can be used at intermediate values, it allows you to create effects that wouldn't be possible in the real world, like halfway-there fabric - or teeth.

The feature you need for teeth is Translucency. Perhaps its value is set too small, or it's not active at all.
Translucency also has some transmission options, and you can set a translucency color. You'll need to make some test renders to find the best settings, because it also depends on your lighting.

Edited to fix typos.

crosswind

I would suggest tweak Translucency + Transmission and SSS params rather than Cutout Opacity... if you use PBRSkin shader, there'll be no Opacity channel. And better add some 'irregular shape' to the teeth (Easy Teeth) to make them not that 'mahjong-tiling'...

FirstBastion

I concur,  Maybe adjust with the translucency channel.

CHWT

esha said:

It's not the correct way, but if it works, why not use it?

That said, Cutout Opacity is not supposed to be used at intermediate values. That property means a surface is there, or not there. It cannot really be halfway there. Like in lace fabric, you have some places where you have threads, and other places where you have holes. In reality you cannot have a half-existing thread. Since the slider can be used at intermediate values, it allows you to create effects that wouldn't be possible in the real world, like halfway-there fabric - or teeth.

The feature you need for teeth is Translucency. Perhaps its value is set too small, or it's not active at all.
Translucency also has some transmission options, and you can set a translucency color. You'll need to make some test renders to find the best settings, because it also depends on your lighting.

Edited to fix typos.

Okay strange thing. I just plugged a pure white map into the cutout opacity channel with opacity set to 1 ,i.e., default value, and it seems to achieve pretty much the same result of getting rid of the mahjong tile look of the teeth and giving it a somewhat less opaque look. Could anyone please explain why?

Matt_Castle

Because activating Cutout Opacity at all forces Thin Walled on for the entire surface.

Basically, any cutout value less than 1, or using a map (even if the entire map is 1 - there's no check for whether the map is 100% white, it just assumes that if there is one, there's a reason) disables Transmission and SSS, which is one of the reasons the channel was removed from the PBRskin shader - it breaks an effect skin is almost always using, so Daz decided that it should be removed from a skin specific shader.

This is due to a technical limitation that these effects are volumetric, and there's no trivial way to map the surface map/UV onto the volume. Is this hole supposed to be through the model, or just a scoop out of it? How deep is that scoop? The map doesn't say.

As such, it's not recommended to use cutout opacity on skin, or indeed anything you want to be using volumetric effects.

CHWT

That's fascinating, thank you for everyone's info!