Cycles: Light through coloured glass

Question

I'm fairly new to blender,I started following this tutorial but the results are a bit far from what I want.

I want to manage to get the crystal material to be transparent, so when the light comes through, it reflects on the ground with the color of the crystal, right now, a hard black shadow is cast.

I cranked up the transmission to 1 and made sure the transparent shadow was enabled but I can't seem to make it glassy enough.

Any help would be appreciated as well as tips to improve the render.

Thanks,

Answer 1

For a crystal, You do not want to use a Principled BSDF. It has diffuse bounce which crystals do not.

Use a glass shader, and set the IOR to be just above 2. This should handle everything.

You're running into a limitation of the Principled trying to do everything, but it ending up terrible at it.

Answer 2

To have light travel through a Principled shader, the alpha needs to be less than 1. See https://docs.blender.org/manual/en/latest/render/shader_nodes/shader/principled.html

By setting the alpha on the Principled BSDF to 0.2, the result will match the image above.