Opacity depth issue

First of all, sorry if the title is inaccurate since I don’t really know how to describe the issue.

Currently in Unreal Engine, any transparent object show other stuff behind even if it’s also transparent, including the faces of the mesh itself visibles through, and that’s where is my issue. Basically, what I would like a way to set the opacity in a way every mesh part that is transparent and behind another transparent object is not visible.
It’s a bit hard to explain and could be confusing, and I think a picture would better explain this :

On left is what I get with Unreal Engine, all transparent parts are visible through each others.
On right is what I get with Sketchfab,the whole thing is transparent, but transparent stuff behind an already transparent thing is not visible. It make the back hair not visible through the head, the face not visible through the front/side hair, etc… It fit a lot better what I’m trying to achieve with this project.

So, does anyone know how this could be fixed ?

Oh, no, I understood you just fine.
You can use Looman’s method on this as well

Down to “Culling Inner Triangles”

Thanks but it doesn’t really solve my issue.
Your solution allow to show allow to show a specific object (or its outline) behind anything else. So I could use it to make my head opaque to get rid of the visible through back part, and then make everything in the word visible through the head, but the issue is my head is only partially transparent and I want these not transparent part to not show through.

It could work if there is a way to include a texture on the object as a grayscale mask (not binary) that apply to the custom depth. Basically using a texture on the mesh that work the same way of the depth mask, but allow different part of it to show through or not.

That would be an Opacity Mask…

It it were that simple, I wouldn’t ask the question.
What happen with an opacity mask is what is on the left picture (and is my issue). What I’m trying to achieve is what an opacity mask does, but without showing the faces of the same visible through, which is what happen in sketchfab. After mu researchs, I see it’s a very complexe problem and it work like that in sketchfab because of the render method (forward vs deferred), but I hope there still is an alternative to achievethis result here D:

you need to combine the 2 methods within the shader. simply prevent any back faces from showing as described in the culling triangles, and map the overall opacity with a mask to get the eyes to be visible.
The map is before, the culling is after, they both affect the same pin. (and it’s expensive to render, but that’s another story)…

Isn’t this Exactly what you need?

Oh I didn’t understand I could combine both, thanks !

I just did this same thing for an Augmented reality companion app for my game (live view of matches in holographic AR)