Realistic Gems

Realistic Gems

Realistic Gems makes the gems in the viewport refract light as you model. With it on, every gem in the Rendered display mode is drawn with real refraction: the light enters the stone, bounces inside against its own facets and comes back out with fire and brilliance. There is nothing to render and nothing to wait for: orbit the view and the stones answer straight away.

It changes only how the gems are drawn. The metal, the materials and the geometry of the design stay as they are.

Realistic Gems is on by default. Click Realistic Gems in the Rendering tab to turn it off, and click it again to turn it back on. You can also run ArtisanRealisticGems and press Enter: with no option touched, Enter switches it on or off like the button. Once you change an option, Enter just accepts it.

Where it shows

• On every diamond and gemstone created with RhinoArtisan.
• Only in the Rendered display mode, or a display mode copied from it. Shaded, Ghosted and the other modes keep Rhino’s usual gems, and Raytraced keeps its own.
• A selected gem is drawn by Rhino as usual, so you still see the selection highlight. Deselect it and the refraction comes back.
• RhinoArtisan remembers whether it was on: if you leave it on, it is on the next time you open Rhino.

Presets

Run ArtisanRealisticGems and click Preset in the command line to choose the look. The preset is remembered between sessions.

The three presets change how much color the fire shows, how far the light splits and how sharp the reflections are.

	Catalogue	Natural	Sparkle
Color in the fire	None, greyscale	60 %	Full
Dispersion	0.005	0.012	0.02
Refractive index	Each gem’s own	Each gem’s own	3.8 for every gem
Environment softness	1	1	0.5, sharper

• Catalogue: the default. The fire is greyscale, like the sparkle of a commercial catalogue photograph. It is the cleanest look to show a piece to a client.
• Natural: leaves some color in the fire, with about twice the dispersion of Catalogue, so soft rainbow flashes appear. It is closer to a diamond seen in the hand.
• Sparkle: an exaggerated, very lively diamond, for when the stones have to stand out on screen. It gives every stone a refractive index of 3.8, where a real diamond has 2.42, with full color and four times the dispersion of Catalogue. It is not physically correct: a sapphire or an emerald also gets 3.8 and loses its own character.

In all three presets the color of the stone itself is kept. A sapphire stays blue even with Catalogue: only its fire turns grey.

Exposure

Exposure sets how bright the gems are, from 0.05 to 8. Raise it if the stones look dull against your background and lower it if they burn out. It is remembered between sessions, and changing the preset does not change it.

Other options

• Refresh: rebuilds the gems and their environment. Use it if a stone you have just edited still shows its old look.
• Off: turns Realistic Gems off.
• Advanced: opens the fine controls described below.

Advanced

The Advanced options tune the effect by hand. They are not saved: choosing a preset sets them again.

• Bounces: how many times the light bounces inside the stone, from 1 to 8. More bounces give more depth and cost more to draw.
• IorAuto: with Yes, each gem uses the index of refraction of its own material (diamond 2.42, sapphire 1.77…), so a diamond and a sapphire look different. With No, the value in Ior applies to every gem.
• Ior: the index of refraction used when IorAuto is off, from 1 to 4.
• Aberration: how far the colors separate inside the stone, from 0 to 0.2. This is what gives the fire: at 0 there is none.
• Fresnel: the strength of the bright rim at grazing angles, from 0 to 2.
• Saturation: how much color is left in the result, from 0 to 1.5. 0 gives the greyscale of a catalogue diamond; 1 keeps all the color.
• Softness: how sharp the reflections of the environment are, from 0 to 6. Low values show every light as a crisp sparkle on small facets; higher values make the facets read as smooth gradients.
• Gamma: the brightness curve of the result, from 0 to 3. Leave it at 0 and RhinoArtisan picks the right one for the display mode.
• Env: the path of your own environment, an equirectangular .hdr image, for the stones to reflect and refract.
• Diag: prints diagnostic lines in the command line. It is there for technical support.

Notes

• The effect needs a graphics card with OpenGL 3.3. If the card cannot run it, RhinoArtisan turns it off for that session and writes the reason in the Artisan Log. It tries again the next time Rhino starts.
• Realistic Gems is a live preview. For the images and videos a client will keep, use Render Studio.
• Realistic Gems is available in RhinoArtisan for Windows only.