How to create gems and precious metals for jewelry in Rhino? – Chaos Help Center

The purpose of this tutorial is to demonstrate the creation of materials suitable for jewelry, with the main focus being on gem materials. In addition to this, it will briefly cover the lighting/illumination aspect as well.

An archive of the project file for this guide can be found here.

An example of the final result when the gem and gold have been applied to the ring.

Overview

The Chaos Cosmos offers pre-made materials for a wide variety of purposes and this scenario is no exception. Both gem presets, as well as variants of precious metals, such as gold, silver and copper can be found in it. In addition to this, the scene will be lit using HDRIs from the Cosmos Browser.

However, the knowledge of how these materials are built can be very helpful and allow for creative and flexible solutions that meet the project’s requirements more accurately. This is why a breakdown of some example materials will be shown in this tutorial.

Gold Material

"Gold" is a relatively straightforward material to create. In this example, the goal is the creation of a "14k Gold" material. The starting point is the base ‘Generic’ V-Ray material with enabled ‘Advanced Settings’ and the settings are as follows:

The ‘Diffuse Color’ should be set somewhere between yellow and orange. In this example, that would be 251, 231, 196 on the 0-255 RGB color code;
The ‘Reflection color’ slider moved to almost 100%;
For the slightly blurry effect of the gold to be achieved, the ‘Surface Control’ should be switched to ‘Use Roughness’ and the ‘Reflection Roughness’ set to a 0.15 value;
For the metallic look of the material, the ‘Metalness’ slider should be moved to 1;
Finally, the ‘Max Depth’ is to be increased to a value of 8.

Gemstone

The gemstone is slightly more complex, but still a rather easy material to create. The starting point is the ‘Generic’ V-Ray material with expanded ‘Advanced Settings’ once again. The settings are as follows:

The ‘Diffuse Color’ set to black;
The ‘Reflection Color’ set to almost pure white;
The ‘Max Depth’ option in the Reflection increased to 8;
The ‘Refraction Color’ set to almost pure white;
The ‘IOR’ is an important value, which must be specific, rather than arbitrary. Since this will be a diamond material, the IOR is set to 2.418, as this is a diamond’s IOR value. Different materials have different IOR values and reference sheets are easily found on the internet. Their use is strongly recommended for more accurate results;
The ‘Max Depth’ option in the Refraction settings is set to 8;
Finally, another important parameter is the ‘Abbe’, which will give the material the distinctive iridescent effect. A value of 65-70 would be appropriate.

Environment

For the environment, an appropriate solution would be the use of an HDRI.

In this example, the “Studio 007” HDRI from the Chaos Cosmos is a suitable choice.

For the “Studio 007” to be applied to the scene, a Dome Light will be created, which will be pasted into its ‘Color/Texture HDR’ texture slot.

Note: V-Ray and Rhino allow for rotation of the Dome Light to be made through the viewport and it is recommended to take advantage of this for the optimal lighting angle.

Additional tips

Gem color

The ‘Fog color’ parameter can be used to change the color of the gem. The ‘Depth’ parameter will control the strength of the fog and a higher value will reduce its intensity. Here, a gentle reddish hue has been used and the result is a Ruby-like gemstone:

The result is a gemstone with a scarlet appearance.

Environment adjustments

Environments can be mixed through a combination of the Dome Light’s Options menu and the V-Ray Asset Editor > Render Settings > Environment parameters. As an example, a different HDRI can be used specifically for for Reflections parameter, while every other aspect of the environment will be controlled by the Dome Light’s HDRI:

Additional light sources

Adding additional light sources like Spot Light or Rectangle lights pointed at the jewelry at different angles can help to “liven up” the reflections and create a more attractive render:

An example of a lighting setup - several Rectangle lights are used to illuminate the ring from different directions.

Caustics

Enabling the caustics could be an interesting choice if the desired effect is for the metals and especially the gems to refract the light and cast iridescent lights onto near surfaces.

Please note that this would increase the render times noticeably.