Sapphire gem material not showing in Bella for Rhino

Hi @jdhill, another thing came up today.

somehow the sapphire material [unmodified] is not showing… while Ruby is fine [ same mineral just different colour so should have the same settings under the hood]

as you can see they do show in Raytrace [syntetic look in the default config… but they do show]

also not directly related question: is there a way to define transparency depth ? so gem stones will have correct colour saturation in relation to the gemstone’s size ?

thanks a lot

It will probably be better to use a Bella Dielectric material, to allow defining the specific IOR for the gem, and the absorption using Dielectric:Depth. You can set the Transmittance color manually in this case, or you can connect a Bella Complex IOR node to the Dielectric:IOR attribute, to render with real measured data. The Complex IOR node has several built-in datasets, or you can find more at But in the case you cannot find a dataset for your gem, you can use the Transmittance color.

I will review the translation of the Rhino Gem types though, to make sure they are doing as well as possible.