Im struggling to make Realistic Eyeglass Lens in Cycles. I did some research about Eyeglass lens, the lens that used in refference is polycarboante plastic lens (CR39) with IOR 1.498. As you can see in first pic the glass seems darkening the eyeball lens behind it, why its happening?.
I use 2 material in lens (second pic), The gloss one is applied to the edge of the lens ,because the lens edges not as refraactive as the front and back lens side, I could be wrong anyway, please look at the node. Any help would be so much appreciated.
One of the problems is, your reference photo has a background environment around it that the lenses are refracting and reflecting.
In your image, the background environment is completely black and hence your glass reflections and refraction will be too.
You aren’t comparing like with like.
Also - a couple of things about the lens edge material.
Why aren’t you using a similar glass setup on the edge of the glasses as on the lens? In real life, it’s fundamentally the same material, just ground instead of polished and so the lens edge will still be refractive. You will be relying on that refraction to transmit light to the edge. Personally i’d try copying your lens glass node to the edge glass and simply increase the roughness value on the glass node.
Given the lens edge is rough, use multiscattered GGX. Multiscatterd GGX counteracts energy loss at higher roughness values and will brighten the rough area. The image below shows two identical rough glass materials on the chess piece (roughness 0.5) - the only difference is front one uses regular GGX, whereas the rear one uses multiscattered)
Definetely, It have no environtment reflection. But I concern, why another glass behind it become so dark? Its like this glass material decreasing light passing through another glass behind it.
Also Its a good point for the edge material, Thanks Ill check it out
Also - make sure the number of transmission bounces is high enough in the render panel. Once you reach the maximum number of transmission bounces, any further refraction will look black.
