View Full Version : Surfacing Gems

02 February 2003, 02:40 AM
Hey, I need some good advice for surfacing A Gem...I dont need percentage amounts..but rather I need some advice on the texture part of the areas...lik eparticular luminosity or color channel textures to put on...any advice?


02 February 2003, 02:49 AM
I know Vangaans made a great gem for a logo id, he'd know, but I haven't seen him around here lately.

here's the one he did, up the top.

02 February 2003, 03:00 AM
Think coloured glass.....

I can't see why you would use Luminosity?
Of course you can use any attribute for a certain look.

What gems emit Light?
Colour = the colour of your gem.....
(Diamonds i use basically a standard white colour) 240,240,240
You may like to add frac noise texture.

I have presets for Rubies, Diamonds, Opals, Emeralds etc...
They also use pretty accurate colours and IOR..
And of course they have an Air surface...

Reflection maps for gems are critical....
And you can use shaders and gradients to great effect too....

02 February 2003, 12:06 PM
As someone else mentioned use air polygons or G2 with double sided.

Try a good HDRI image for creating the multiple busy reflections/refractions with a more realistic environment. Other than that, the surface is pretty close to regular glass (remember not to use glass's refraction, air polygons go to 1.001 unless you have trace refraction on). Depending on the type of gem you may want to have some colour filtering. As for luminosity. That would be bad, it can "burn" out your reflections which are vital for a gem.
Basically the busier the image the better it will look I've found.

Good luck.


02 February 2003, 03:38 PM
Dave Jerrard (sp?) did an excellent tutorial on this in a book and I think it is online somewhere.....

02 February 2003, 08:17 PM
Originally posted by proton
Dave Jerrard (sp?) did an excellent tutorial on this in a book and I think it is online somewhere.....

On Mohh's site right here:

CGTalk Moderation
01 January 2006, 11:00 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.