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Hey guys, I have a challenge. I have been painstakingly studying the cuts and proportions of gemstone cuts for diamonds (the common ones like round brilliant, oval, princess, etc.) and noticed that the one's available on most 3D applications (like Rhino and Max) are not really the "ideal" cut for diamonds. They are not the industry standard cuts used to show off the best balance of brilliance AND desireable refractive pattern. The current 3D models available do not produce desireable long slender refractive patterns, for example, on the round brilliant cut.

For example, none of the round brilliant diamond cut models available for most 3D applications are actually the true cuts used in most jewelry today. Below you can see the side profile of an "ideal" round brilliant cut used in the jewelry industry today and a less desireble cut offered for most 3D apps
The latter "wider" facets on the pavillion (lower half of the diamond)produces more splotchy wide refractive patterns.

You can see above that the area shaded in red is much noticeably wider than that shown on the other "ideal" cut. This produces quite different results in rendering on any application, including Maxwell. The former cut is prefered because it produces a more desireable pattern in the refraction of light.

Is there an application that has "ideal" and accurate cuts of diamonds as 3D models? So far I have not seen any used in today's jewelry industry.

Perhaps we should build our own exclusive Maxwell members only "ideal" gemstone cut 3D model library.

You might look at GemCad...

http://www.gemcad.com/

G.

Or you could try grabbing these free models of gems and check if they're usable for your work.

http://www.3dlapidary.com/

/ Max

I think the models from 3dlapidary have the same problem. They are not ideal cuts.

I will check out gemcad today, thanks.

Will anyone really notice that ? i mean the gemstones are all transparent with high refraction values and dispersion and reflection to some degree so you won't really see if the cuts aren't 100% accurate down to the last slice of the stone. But ofcourse this depends on your audience and your own wishes/demands.

Just thinking out loud now..

/ Max

Well, there is a very noticable difference in the appearance of the patterns. The slightest difference in diamond shape can impact the refractive pattern immensely - each refractive bounce amplifies the discrepancy.

I am trying to achieve photorealistic renders with diamonds...This means the diamond's refractive patterning has to behave as it does with an ideal cut (usually seen on professional jewelry photos). It's easier to explain with photos and renders. I'll see if I can conjure some samples to explain what's happening.

I understand now what you mean, then you do need some sorta software to give you precise cuts of the gems. Probably what Gavin suggested should do the job for you. I hope so

But please do show us your results, i'd like to see them.

/ Max

It's been a while, but at one point I seem to recall hearing from a jeweler that (at least for diamonds) the "ideal cut" isn't actually very common and they are special-order kinda things, so most diamonds are sold with the standard "brilliant" cut.

But I in no way claim expertise in this area at the moment.

G.

There are so many slight variations of the round brilliant. I'm looking for the one you normally see in professional photos - and this is not the same as the standard round brilliant seen at 3dlapidary.com or on gemcad. I may have to create my own models to achieve this.

Apparantly Diamcalc has a huge library of AGA approved ideal cuts. I am going to investigate further and see if these models can actually be used in 3d rendering software (for use in Maxwell of course).

I will keep you guys posted.