How do you make parts of Genesis 9 body or head transparent?
lipluck81
Posts: 30
in The Commons
How do you make parts of Genesis 9 body or head transparent?
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It depends on which parts, and to what end. Some can be hidden by hiding a bone, a transparency map could be used, the Geometry Editor could be used to hide areas tewmporarily (or assign them to new surfaces or bone selection groups, to be combined with oen of the previous methods,) or a geoGraft could be used to trigger hiding and optionally fill in the hole left behind (though that requires some modelling work).
Yeah ~~ completely hidden ？ or like 'crystal clear' ？
I load Genesis 9 into my scene. I click the Head surface and am able to set it's Cutout Opacity. But here's the problem though, if I apply IVAR 9 mats to Genesis 9, the Cutout Opacity can no longer be used, it just disappears, even if I show hidden properties.
Correct. PBRskin does not include cutout opacity, since it is intended to be skin.
This sounds like a major problem. In the history of 3D, no other 3D application has this limitation. Making a material tansparent is like the most basic aspect of 3D.
It's not a problem. Why was it named as ' PBRSkin ' ? In physical world, normally human's skin could not or should not be 'transparent' / 'crystal clear' but only has SSS effects at most. If one wanna make 'transparent effect', just use Iray Uber Shader loh.. In fact, PBRSkin Shader could be customized by using Shader Mixer to include cutout / refraction etc. but that'll be a complex procedure...
Skin is more translucent than you might realize. In fact, subsurface scattering only occurs BECAUSE of that translucency, and that's also why you can see your veins through your skin, etc.
Of course.. no one can make SSS effects without the weight of Translucency.
Translucency is not the same as opacity in iray - translucency simulates light travelling through a solid medium and opacity is just how visible something is. Ultimate the issue comes down to iray SSS not working when an opacity map is used. Rather than nvidia fixing it - if it is even fixable and still remaining 'PBR', this is the 'solution'.
Yea, they're different things.. Translucency is related to diffuse while cutout opacity is purly an efffect on geometry. But not sure the problem you mentioned, what exactly is it?
PBRSkin is simply a name for a shader. The shader itself is not some magical skin making shader, it is merely a name used by Daz to advertise it. You still have to know how to make skin look good in various lighting, PBRskin doesn't change this and there are plenty Daz store products with PBRskin that look no better than the old shaders. You may find threads where people think it looks worse. All PBRskin does is add a couple new options, the biggest thing it adds is tiling. Previous shaders had no tiling features. That is all. This has nothing to do with skin! In fact, there are a few fields that PBRskin do not have compared to the previous shader, so it is not just opacity missing.
But there actually is a reason why PBRskin lacks an opacity value, that is because it doesn't work correctly with the tiling options. I cannot remember the exact technical reason, but since Daz was not able to make it work, they disabled the opacity setting for users with this shader. I suppose they didn't want complaints about that certain thing not working correctly with opacity.
So if you wish to use an opacity map with Ivar 9, you will need to use a different shader. If there are no tiling textures on Ivar, you can pretty much do this with the standard Iray shader. There is only one new field in Dual Lobe that the standard shader lacks.
Another option is a shader made by Soto included with Breast Utilities 2. https://www.daz3d.com/breast-utilities-2-for-genesis-8-and-81-females
This shader has tiling but also replicates the classic Iray shaders most of us are familiar with. It allows for tiling in multiple fields. So it is like a hybrid of PBRskin and the old shader.
However, the technical issue that Daz ran into still exists, so there may be situations where the shader doesn't look like it should with opacity maps in use. But at least you are free to try it out for yourself and see, and you have the freedom to find a solution.
If you are just wanting to make that material zone transparent, then just apply the Iray uber base shader to it and the cutout opacity slider will return. If you want it back, just reapply the skin you are using
So, the solution is to downgrade to Iray Uber base shader? I tried applying Iray Uber base to Ivar 9, and when I go to render, it looks wrong, very wrong. Is there a script or some kind of automated way to convert G9 PBRSkin to Iray Uber base automatically? I could hypothetically do it manually, but that would take so long.
IMO, DAZ needs to fix this; add cutout opacity to genesis 9 and get it working right. I don't need to use tiling, so I'd prefer to have a cutout opacity option for PBRskin, I'll deal with whatever problems it causes. This is a severe limitation that hampers my ability to do creative, out of the box things.
I guess I'll email support, I suggest you guys do the same. I know it's a lot of annoying work to have to email support, but just please do it.
Not being able to set cutout opacity is crazy to me, truly crazy.
Still, on a side note, I really do love a lot of things about Genesis 9, it's just heart breaking we can't do something as simple as set cutout opacity.
Are you aware that if you use cut-out oppacity in a surface, you are not able to use SSS?
So if you want to use cut-out oppacity you need to use it for the whole surface, and thereby there is no difference to change the shader.
Really? Hmm. If someone could get this working as a product, I'd buy it.
This is 'crystal clear' transparent with iray uber shader, with refraction.. in order to be 'visible' in viewport.
SSS is switched off when a map is added to Cutout Opacity (or the value is changed from 1.0). Apparently it's a technical limitation but I can't elaborate on the nuts and bolts of it.
I suppose, technically, the only 'realistic' method to create a transparent surface is Refraction Weight - think of Cutout Opacity similar to using a mask or alpha channel in Photoshop, or even layer opacity.
Okay, got it ~ and mostly agreed. Perhaps we may 'dig out' some clues from the 'node relationship' among Cutout / Transmission / Scattering... worth some studying...
There's a mix of different explanations above as to why Opacity isn't in the PBRskin shader, but one thing I can confirm is that in Iray, activating cutout opacity does force off all transmission and SSS effects. The thing is, things like transmission and SSS only really work properly when the model is "watertight", and cutting holes in the model messes with that - and, more than that, how is Iray supposed to take a cutout map that relates to the 2D surface of the object and translate that onto a 3D volume? It's not a simple problem; an opacity map that's supposed to chop off a limb would need to work out how to interpolate across the limb, but a cavity in the front of the torso... well, how deep is that hole supposed to be?
For an illustration of what the issue is, refraction maps and volumetric effects do still work in combination... but try turning on refraction on an Iray Uber character skin. Because the refraction maps cannot be translated properly to the other volumetric effects, even at maximum refraction strength you still get the haze of all the volumetric effects.
So, Iray either has to make a choice between opacity not working properly when volumetrics are applied, or volumetrics not working properly when opacity is applied. And it's gone for the latter.
Adding any opacity to PBRskin would break it (and it does with Iray Uber too, even if you might not have noticed thus far) - so given that PBRskin as a shader is optimised specifically for skin, it's entirely logical for Daz to have chopped out those blocks from the shader in order to make the whole thing more efficient and optimised for its actual intended purpose.
TL;DR: It is not possible for Daz to fix PBRskin to have opacity, because opacity breaks skin.
Just so we can clarify a point that keeps coming up in these very similar posts...
It's not that Subsurface Scattering (SSS) CANNOT work with opacity - it's just that there is a technical issue preventing use of it in the PBR shader preset. The Poser materials options allowed it and it worked just fine. Technically speaking transluscency and SSS ARE forms of transparency and so the from a technical perspective it's not unreasonable to expect a transparency/opacity option for the PBR shader (which is why it keeps getting asked for). Now I don't know how difficult that would be to wire into the PBR shader, but it's really getting on my nerves when people keep asking "why you need that," or saying, "you don't need it." I would like to have it AND ambient/glow option in order to be able to simulate (in a quick and rough manner) light passing through earlobes. But PBR has neither that I can locate. If we can't get PBR to have these things, how about DAZ figure out a way to move the PBR good things at least - back into the Iray Uber Shader? If you can't go forward...back up and take a different route. After trying to find opacity myself today and then running across a billion and one other people asking for it - I think it's an appropriate avenue for DAZ to take a deep look at. How many of us are rendering outside of Studio anyway? A magic skin preset with all the goodies available would sell like the proverbial hotcakes. I myself would throw many dollars towards it.
This is a technical hitch folks...not a wall. There should be a path around it. Kudos to whomever finds it. My money is waiting impatiently...as are my earlobes.
PBR means Physically Based Rendering. SSS means Subsurface Scattering, which implies that the entity has volume. Opacity (plain) works on a zero-thickness surface. Ambient, as oposed to emissive, is also not a physical thing but a way of faking it at low cost. Iray is quite strict, by design, about being physical - this is why the "bug" with emission and transparency was fixed, breaking ghost lights and changing rhe way transmapped emitters (such as flames made of planes) behaved.
That means that, within the Iray design paramaters, Cutout Opacity is an issue with SSS,m and Ambient is an issue all around.
In Iray, using Cutout Opacity on a surface always forces on Thin Walled; it's not something that the Uber Shader gets right and PBRskin gets wrong.
It might not be obvious with certain skin settings. If the translucency is low or dark enough, the difference can be minor - and quite a lot of older skins do this, so this is one reason why it might have appeared that it used to work. But most newer skins favour a stronger translucency to more accurately represent how skin actually interacts with light, and here the difference between Thin and Thick walled is very apparent:
This is with the Uber shader, and the only difference between the materials in these pictures is that a 100% white opacity map was added to the torso in the second:
Cutout Opacity forces on Thin Walled in Iray. It's a limitation of the render engine that shaders cannot sidestep.
There are theoretically be ways for Iray to address this, such as but those are all changes that would need to be made on Nvidia's end.
Having the volumetrics disabled dependent on the opacity alpha test would create an effect somewhat like this (which I did by outright cutting a hole in the geometry using Blender).
However, I could certainly see that adding such a calculation into the renderer could potentially bog things down, and it may be that Nvidia doesn't want to have that overhead present for what is generally a somewhat niche use - although I could potentially see it being integrated in a similar manner to something like the caustic sampler, only turned on when something in the scene needs it.
(Although that said, I use the Caustic Sampler a lot for times it's not specifically designed for. It really seems to help with propagating light through interior spaces. And while it roughly halves the sample rate, it actually seems to provide cleaner results in less time, with each sample doing much more work.)
Easiest way is a Iray Section Plane Node, but it cuts off everything on the wrong side.
That is a hugely disturbing image ... and I am absolutely going to have to try that in the future. :P