started blender a month ago.

I'm trying to combine nodes to create a specific skin effect on BLENDER 2.8, Eevee.

The one you would see on the chin of a breathing frog. A skin really tensed, with a gradient of transparency opaque at the bottom, nearly see through at the top of the "sphere".

enter image description here

I tried all the advices to do glass, plastic or I don't know. None of them where satisfying and had any real control over the area of transparency, nor the gradient I'm looking for. I Tried to combine it with a fresnel, I was close but no gradient, even with a color ramp.

I found out this awesome video solving the problem throught texture painting:


It works for me. The problem is that I'm not using any texture, only nodes. I don't know how to paint on it.

Do I need to first finish my mesh, somehow extract the "node texture" from it, re-apply it, and then paint it with transparency?

Any suggestions? Thanks a lot for your time.



Here is a node setup to achieve the transparent gradient sphere effect:

node setup render result

I'm using a Mapping node to control the direction of the gradient, Gradient Texture node for the gradient itself, and a ColorRamp node to control the transition. For the transparent part of the object, I'm using a glass shader with IOR very close to 1 (or it will look like real glass), and 0.6 roughness to make the object behind appear more blurry.

And make sure you enable screen space refraction in both render and material settings, or the transparency won't render correctly.

I don't know why you are trying to avoid using textures. While this procedural setup works well on a sphere, I don't think it will work if you are going to apply it to something more complex (like a frog model). Since it's using a simple linear gradient, it's very hard to make it fit perfectly on the frog's chin. I would recommend using texture painting if you really want to do that.

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  • $\begingroup$ It seems that you got it perfectly right. Thank you very much for your time. I found out a solution as well going to post it too! $\endgroup$ – Arthur Jul 5 '19 at 12:00

Scarish solved the problem really simply, see his comment.

I found out myself another way to solve it throught texture painting. This one gives a lot of control where you wish to have transparency and how much.

Here it is :

enter image description here

I'm not that comfortable with nodes that's why i'm struggling. The answer is pretty simple though.

1 - I added one more mix shader so that the transparency is applied on my Principled BDSF shader and everything that go with it. (That was my main problem).

2 - As you can see, you can pretty much draw as you wish to manipulate the transparency as will. (stretched skin, globules... anything organic or even more applications that I don't have in mind.)

3 - See the result. (note that I added a red sphere inside). The translucid part is a bit noisy, however for my very problem it feels like it's the best I can do for realism.


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