I have been trying to recreate the material seen in the picture without success, this picture is an electron microscope image of diatom shells, they have 2 important characteristics. first, since they are microscopic and photographed using electron microscopy they have quite a bit of fresnel around the edges, this can be achieved easily enough by connecting a layer weight nodes fresnel or layer weight factor into a colorramp for color.second, the shells are made of silica (basically glass) which has very high transmission and transparency. i haven't really been able to achieve a material combining these characteristics in any way that looks similar to the image. if you know of a good way to tackle this material, please answer, and thanks in advance
]1
2 Answers
A Fresnel node can be used as factor for a Mix Shader between a Transparent BSDF and Emission Shader, in order to achieve the glow at grazing angles. The Facing socket from the Layer Weight node allows to add a slight glow for the angles in between. Finally the Is Camera Ray output from the Light Path node is used to only show the emissive material to the camera, meaning the object itself and objects near by won't be affected by the emitted light.
-
$\begingroup$ this material looks great, and is exactly what i was looking for! thanks. $\endgroup$ Commented Dec 7, 2019 at 14:47
The glass optical properties are not relevant to what you're seeing in those images because scanning electron microscopes don't use light. Instead they detect electron emission. I think the piece you're missing is that electron emission varies with how "pointy" each part of the model is. One could try to model that using a properties output in nodes (cycles literally has a properties output called "pointyness" - doesn't work in Eevee though) and use that to increase the brightness at edges and points. That is what's going on inside the scanning electron microscope, so it should be able to generate similar renders.
